I recently put together this computer:
 
Asus P5K-E wifi motherboard
E6750 core 2 duo
Crucial Technology Ballistix BL2KIT12864AA804 2GB kit DDR2-800 PC2-6400
Geforce 8800 GTS  
WD Raptor 150g hard drive
OCZ GameXstream 700w power supply
 
The problem is that the computer will fail to POST, but it's random.. or seemingly random. The computer when it does POST works  perfectly fine, I've run stress tests with Orthos, played 3d games for hours, no problem at all. But if I do a full shutdown and try to turn it back on, it fails to post and I have to reset several times before it does.
 
Here is what happens in detail. I hit the power switch, fans come on, lights come on, everything seems to be okay, but no beep and no video. The video card fan will then blast on full. Then I'd have to hit the reset switch, and the system will turn after a few seconds, wait another few seconds and come back on. Now the process just repeats. Eventually I get lucky, I'll hear the beep and the computer will post normally.
 
I think this is the asus motherboarding recovering from a failed POST, usually after it finally comes back on it'll say Overclocking Failed. It will usually load up the default settings for bios. But that's random too, even when I leave it at default settings with no overclocking, this will happen and the motherboard will underclock it even more. basically my CPU is at 2.66 (333x8) so it will revert to that, or it may go even lower and go to 2.1 (266x8). Normally I have it run at 3200 (8x400) in which is it very stable as I stated in the first paragraph.  
 
What's even more annoying is that once the motherboard does the recovery thing, and for example it sets my cpu to 2.1 (266x8), no matter what I do to change the FSB stays at that setting. I can change the FSB to any number and it will save that setting in BIOS, but in reality doesn't change because CPU-Z and even in the POST screen it'll use my FSB at 266 and report my speed at 2.1. Sometimes if I'm lucky, it will actually change it but normally it gets stuck at that setting. The only sure way I can get it working normally again is if I unplug the power cable, wait a few seconds then plug it back in. That resets something in the motherboard..what exactly I'm not sure.
 
As I said its seemingly random, I can get it working at 3200 is if it actually POSTS and keeps my settings in BIOS. But even If I don't overclock it and leave it at 2.66 it will do the not posting thing and sometimes go down to 2.1.
 
I've tried clearing CMOS many times by removing the battery and moving the jumpers.  
 
I've tried removing a memory stick, didn't seem to affect anything.
 
I've tried flashing the bios using USB method, tried 602 and 503, they both do the same thing.
 
I'm pretty sure the power supply is fine as the computer work great if it does start
 
Still happens even when I remove the harddrive, dvd drive
 
Tried disabling various options in BIOS ppl in other forums have suggested, but none have worked so far.
 
 
any suggestions ? or should i just return this motherboard, sigh  
 
Thank you
 
 

Check the asus forums.  There are sticky threads on troubleshooting the no-post situation and overclocking failed message.

i've tried, didn't see anything helpful in there other than the usual its your power supply, its your memory, responses.
 
I've tested the power supply, its in working order. Strange thing occurred when I was about to switch out my memory though. I turned on the computer with no memory sticks installed and it still had the same problem, no beeps, no video, but fans and lights on. Then when I reset it a few times it finally recognized I had no memory in there did the 1 long beep 2 quick beeps to signify no memory.

I'm experiencing exactly the same problem.
 
I've also browsed the Asus site but have been unable to locate anything relevant.  
 
Can anyone point me in the right direction?
 

Same problem here.  I've got Crucial Ballistix 8000 RAM running at 1066.
Eventually, it completely died and could not be brought back from life.  I RMA'd the MB (they told me to RMA the RAM, but I argued that 2 sticks going out seemed unusual).  They cross-shipped me a board, which after some strangeness did boot.  But, it too had the same occasional no POST.  Today, I'm dead again.  I'm thinking of RMA'ing the RAM just to remove that possibility.  But, I think ASUS F'ed this board design somewhere...it might be a ASUS/CRUCIAL thing?

Guys, I have had the exact same problem with my Asus Crosshair and my OCZ sli ready 1066 ram.  
I have rma'd 2 boards; tried 100 ram combo settings and every concievable bios change or "solution" from all the forum sites i could find.
Have you guys run a memtest on each individual ram stick?
I have and mine are 100% no errors. I have even tried the most skeleton layout setup outside my case on some cardboard to eliminate all posibilities.
My conclusion is that a range of Asus chipsets have huge holes in the bios or the boards in general have some crazy big bugs that effect high end ram. This problem seems native to Asus boards ( Commando, Crosshair, Strikers,P5Ks) so Im hoping they put together an amazing bios for the next release. My problem i think is that my board tries to let the EPP on my OCZ ram take over and port the settings into the bios which breaks something. If i do amazingly post and quickly change my voltages, timings and fsb (even just stock and 800fsb ) it runs super stable in orthos,prime95,3dmark and superPI. Its when I cold boot that 9.5 times out of 10 now it just WONT F&$^T$&^CKING POST! Driving me mad.
As long as I just keep resetting and not shutting down ill be fine
Cant live like this forever.
The problem is the consitency of the problem with this damn posting.
PS - apparently loads of people have success with removing any connection from the front usb cable to the mobo - i.e unplug this and try again. Something to do with a faulty connection.
Im not going Asus next time - thats for sure.
 
Let me know any updates.

I have a similiar problem with a P5B/wifi , and while this is not a meaningful solution, just a possible bandaid, what i have done is let the system run with out posting for 5-10 minutes then restarting it, it usually posts after that. I also have replaced the PSU/ Ram etc...

I'm having the exact same problem too with my p5k...
or rather, I was.
I unplugged and replugged everything, and now what happens is that unless I switch off at the mains, the fans all always spinning - even when the pc is supposedly 'shut down' and before i turn it on!
 
I don't think it's a RAM thing (mine is OCZ) and my pSU has been working fine for 2 years...
 
anyone got anything else on this?

I had this problem with my P5B. There does not seem to be a fix. I have RMA'd one board and the new one they sent me doesn't post either. I gave up and bought a P5KC. Haven't had a post issue since.

I'm having the exact same issue, I find turning it off at the powersupply allows an immediate start
not a great solution, hopefully asus will put out a new bios to fix this issue

i don't know if its only Asus because i get the exact same problem on my GA-P35-DS3L board. i built this specially for overclocking, so this kinda irritates me having to stay at 1.8Ghz with a pentium 2160.

hey guys.  Same issue here.
 
I read on another forum to change all the overclocking features from "auto" to lower settings.
 
For me, changing the ram speed form "auto" to "ddr-833" (i think) seems to have cleared it up (most of the time)
 
The only time it gives me troubles is in the morning (after it's been sitting off overnight).  Which is why I'm still looking for a fix.
 
Well, I hope that gets you guys closer.

Hi, exactly the same behavior observed on my Asus P5K-E. My bios is the last available (0805), OC@3200 perfectly works when it posts.  
It occurs randomly but a 'cold' case helps to reproduce the problem.  Turning off/on manually the PSU is the only workaround I found.  

I had the exact same problem with my p5k and p5k deluxe.
I found a workaround and it has been fine since.
I did the memory swap.
Took out the dimms, which are pc8500 crucial ballistix and I put in 1 stick of pny ddr2 667 and the system posted first try.
Again, to be clear, no post means no beeps from the mobo, no bios at all, just fans and stuff, but no vid signal or otherwise signs of life.
 
Went into the bios and changed the auto detect settings to 1066 ddr frequency and shut down, then i added 1 stick on my ballistix and rebooted and it posted fine, then I shut down adn added my other 3 dimms and started up again and I havent had a problem.
 
I tried a new mobo, psu, vid card, etc.. and then I tried the memory swap and that was what did it.
Dont know what would cause the issues to begin after 6 months of use with no issues at all, but I was relieved to fix it.
 
i also found that leaving the dimms set to auto for all the cas latency settings and stuff was the only way the memory would remain stable.
 
I run the 1066 mem at 1000 , fsb 500 x 2, and my multiplier at 7, so my chip is slightly overclocked to 3.51 and running a 1:1 ratio with the mem and fsb, this has ben fastest and the most stable for me.
When i changed the latency settings I was 80% stable but would get bsod's once in a while, after going to default settings on those setttings I havent had a single bluescreen.
 
Lump
 
specs  
 
Asus p5k
Intel duo core 2 extreme x6800 @ 3.51
crucial ballistix pc8500 4x1 gig @ 1000 mhz
Evga 8800gtx superclocked 621/2000
X-Fi extreme gamers card
7800 inspire 7.1 speaker system
Antec trio 650 psu
Plextar 16x dual layer dvd/rw
seagate 400 gig sata 7200.10
Zalman 9700 cpu cooler
Thermaltake Armor 8000bws full tower
dual boot Win xp pro/ Win Vista ultimate 64
 
http://service.futuremark.com/compare?3dm06=2135491  11936 3dmark 06

 
Yesterday I flashed the bios to 0806, no OC, and today it posts fine.  
I should observe if it's stable in the day.
If yes, it might be an OC issue, maybe a more fine tuning is needed.  
 

relax ppl... its just some bios bug that everybody is having .. the boards work fine..
 
i fo example have a P5E mb.. with latest bios it randomly fails to post ... with the simptoms being just as many have described above.... then i tried with 1st bios and it boots fine every time ..(sadly the 1st bios has poor performance so im stuck with the latest .. anyway i got used to it after a while...
 

 
That is what I was going to say, the Asus P35 based mobo's have had a horrible track record from the beginning. Check out NewEgg's reviews on any of the Asus P35 base mobo's, you will see a LOT of unhappy people. The problem lies in the BIOS acting up and deciding when it wants to boot, like a ghost in the machine. My Asus P5B Deluxe WiFi AP mobo died an early death so I replaced it with the Asus P5E X38 which so far has a perfect track record for working out of the box.  
 
Theres 38 reviews at excellent rating, 5 good and only one average. These P5E, P5E3, P5E3 Deluxe and P5E3 Deluxe WiFi are turning out to be very reliable mobo's so far. The P5E3 Deluxe WiFi has the ability to surf the web after 5 seconds of pushing the power button, you don't even have to launch the OS to browse the web. Sorry for the rambling my system has been down for two week. Asus has followed Gigabyte on having very good quality mobo components like Japanese made long life Conductive Polymer Capacitors, industry leading high quality power components.
 
I really do hope you find a fix for your BIOS reboots.  

 
Well. I did RMA my RAM. I temporarily used some Kingston to hold me over.  It did it too.  Got my new Ballistix tracer RAM...it does it too.  This is F*ing ridiculous!  ASUS should fix this before they have a FLOOD of RMAs!!!

If you can still return your mobo then I'd do that and get one of those P5E mainboards, their track record is excellent!

I have the Asus P5k-E and having the same issue! But guess what? Last night (Dec 6, 2007) I downloaded from Asus website Bios firmware ver 901 11/14/2007 that said it fixed something to do with S3. I did not understand at the time. Anyway this morning I noticed that it is gone from their website. I have not rebooted my PC since to see if it fixed anything. Just thought I would drop a note. The board seems very stable otherwise.