Greetings; This is my first post on this forum, so I'll be as concise as possible. My system specs are as follows:
Coolermaster Centurion 5 case
Antec sp 500 PSU
Corsair twin x ddr 400 memory-2 x 512meg
Asus A8n-Sli Deluxe MB
Opteron 170 cpu
Asus Geforce 7600 gs video
DVD-rw drive and floppy drive/card reader combo
I built this system and have had it running well for about 1.5 years and recently after cleaning (blowing dust out of case), My system failed to start up. I checked reviews for psu (which where very positive at time of purchase) from Newegg, and I discovered that quite a few of these had failed within the same time period as my purchase. I contacted Antec and they informed me that they had discontinued that model, and much to thier credit they promptly sent a replacement. The replacement is a Neo HE 500 watt.

Ok, so I replaced the psu and started my system up with no problem and everything seemed fine. I went into bios and set it up as it was previously, (overclocked to 2.8 ghz @ 1.4 volts prime stable). Everything seemed fine and I ran some bench marks and did some work (estimating and bookeeping) the rest of the day and shut it down for the evening. Next morning, I pushed the power button and lights came on briefly and fans started to turn, then shutdown immediately. I tried this several times (5 or 6) and finally it stayed on. However, when posting, it said "checksum error, defaults loaded". I continued to bootup at default settings and everything was fine albeit much slower. I then restarted and set up bios again as I had it previously and continued bootup and again, no problems. I seem to be able to restart at any time and it boots right into Windows with no problems, however the problem happens every time I shut it down completely and attempt to start up again, multiple times of pushing power button before system will power up completely and then it starts with "defaults loaded".

My question is could it be a problem with the new psu, the power switch or something else? I have checked all mb connections and reseated cards and memory. And why would it continue to load defaluts when finally staying powered up? Any ideas or suggestions would be greatly apprediated.

bios battery perhaps...

Does this happen when the system is not overclocked?

Hello again;
I thought about the cmos battery, because when it loads defaults, the time and date go back to the original bios date. And in answer to the other response, i'm not sure about bootup when not overclocked. I will test that. Thanks for the ideas.

It could be the result of 'failed overclocking', which is not to say that you can't OC to 2.8, but if for some reason your voltage tweaks are not kicking in after a cold boot then you may not be able to hit the 2.8 until you have reset the tweaks. Just a thought.

Some MOBO will load defaults automatically after x number of failed boots. So maye a battery issue and maybe not.

Well it is definitely not cmos battery issue, and is not a failed overclock. I replaced the battery, and tried cold starting several times at default settings and the symptoms are still the same. It takes about 5 pushes of the power button for it to stay on. Once its on, it runs great and temps are between 37 and 40 for cpu. Anyone got any other ideas?

just saw your new post, any better?

i had run into similar problem long time back, i suppose it is due to the PSU, if that doesnt resolve then try flasing your bios. The resetting of bios can be attributed to CPU frequency.

Well, I have flashed my bios and no difference. I have left it running day and night so as not tax my power switch or psu trying repeatedly to get started. I am thinking I will contact Antec and see if they can give any help. Another possibly related problem is that when I try to run Pcmark 05 or 3dmark 03 they try to load and then my system restarts. I have run prime 95 and sp2004 and everything seems stable, even good temps under load. I am at a loss as to what to do next. I hate to have to take the psu out of my wife's computer just to see if it exhibits the sames with different psu, but that may have to be my next move.

I can understand your frustration & more so when you have a latest system and things go unexpectedly wrong, intriguing as to why only advanced users face intricate problems?? one thing is for sure be patient and things will fall into place. goahead and try out the PSU from your other system or get a cheap one just to test. Probably a component inside your PSU (like capacitor stuff) is not charging up after a system is turned off for a brief period.

do remeber to put a message after you have resolved.

Among the other things check that the Bios reset jumper is in the right place.