Hi Guys,
 
I have a problem I need help with.  
 
This being only my 2nd build.  
 
My Mobo is Asus P5P800. I bought it used from a guy who overclocked the board. I used a new CPU P4 3.0 I bought and new (2 x 1GB) DDR-400 CL 2-3-3-6 Dual Channel Kit Retail TWINX2048-3200C2PT from Corsair. ( these were on the list of compatible ram, according to Corsair) On startup I went into the Bios and change everything to the recommended standard settings.
 
Here issue #1: The build, with both sticks of ram,  will turn on and stay on, but nothing comes up on the monitor. No splash screen or OS.  
 
With just one stick of ram everything runs fine. Boots up, XP pro SP2 is up and running.
It doesn’t matter which stick I leave in, either will work.. just not both together.
 
Issue # 2: After I’ve tried starting with both sticks and failed. The next time I restart with just one stick, a screen comes up saying that the overclocking failed, giving me the options of F1 (?) or F2 (which sets everything to default).  
 
So I pressed F2 and everything fine.
 
However, I have no idea if these two issue are even related. What do I need to do to get this up and running with both sticks of Ram?
 
My Build
Asus P5P800
Cpu P4 3.0
DDR-400 CL 2-3-3-6 Dual Channel CORSAIR
Sapphire ATI RADEON™ X1950 PRO
Seagate 250 sata drive
DVD writer

the overclocking failed is just a "Damn i did not boot...loading defaults to boot". If you just go into the bios and exit your settings should not be hurt(at least in most cases)...its just a precaution.

Have you tried different combinations of slots...so both in blue(i think this is needed for dual channel mode) check, black, check one blue and black?

Also did you check if that ram needs more voltage? sometimes low latency stuff does...

You said "Also did you check if that ram needs more voltage? sometimes low latency stuff does... "  
 
I know the voltage for this rams is 2.75V. What do I look at in the Bios to make sure it set right and what do I set it to?

Place holder....looking in the book

_____READY______

Do your settings with one stick in then save...power into the bios then kill the power...this avoids the overclocking fail message.

To set your ram timings(i assume you did this)
Bios -> Advanced -> Chipset -> SPD Disabled -> Set it
until you get this solved you may want to turn off Performance Acceleration Mode

Voltage Time...

Bios -> Advanced -> Jumper Free Configuration -> AI Overclock Tuner -> Manual(setting)
The only thing you want to touch in here is ram voltage

Look for "DDR Reference Voltage" and select 2.75

Save your settings restart. enter the bios make sure they are still there. Power off the system(once again this is just to avoid the oc fail message on next boot). Insert the other stick or ram and cross your fingers. Make sure both sticks are in blue slots...or both in black slots if you want Dual channel mode.

I hope this helps...

Try a stick in ALL the ram slots...bet one of them is dead or shorts out with a stick in it.
The other problem might be that the MB needs to be sent in and re-cap'ed....the MB's pwr supply for the ram may be dieing and can't take the small extra currant load.
 
I have watched this happen on a DFI MB...the monitor program that comes with it shows both the PSU voltage comming in (like Ausus probe) -and- it shows the voltage on the MB as it goes into the 12/5/3.3 volt areas (like the RAM).
I could see it droping on the RAM volts for about 6 weeks befor it would no longer boot yet the PSU volts were good.

I say increase RAM voltage, then try  booting. If you can boot, run Memtest86+ to check for errors.

Have you tried reflashing the MB sometimes the latest version of BIOS can help.

updated my post above...set that voltage and see how it goes...

thanks again for your time and suggestions. Before I set the voltage, I have another. Since I put in a new CPU P4 3.60 800MHz FSB, the old one was P4 2.66Ghz 533 FSB, do I need to change the system clock setting or anything else?
I'm a total newbie so please offer up any steps I should have done but may not have.
 
Also, I'm really uncertain about how to do the system clock.  I've spent time reading about it, but I'm still uncertain.  Can you help, please?

The board should auto detect. the only thing you should need to look at is the DDR Reference Voltage and timings.
 
Worst case scenario, you can always reset the cmos if your settings don't take.

If you want to make sure all setting are at default in the bios there should be a "set to default" option.  Just use that and everything will be back to where they should be.