OK Guys i need ur help ...
this is my config .. Asus A7n266-E(nforce1), Athlon XP 1800+ (palomino) and NOT OCed, 1 X 256 mb RAM (PC2100) , onboard VGA/sound, 300w PSU
I've been using this for like a year and a half and i've loved it. But since last week it's been showing some very strange symptoms. The system runs for an hour approx, and then ..POOF ... it restarts and fails to start again, giving long beeps in a (endless) loop. If i do power it off and on again soon, it does the beeping again or it works for a few mins/seconds and then restarts/freezes sometimes giving a blue screen, messages varying from "disable caching/shadowing .. remove new installed components ...upgrade bios ...starting memory dump", "general protection failure", "IRQL_LESS_THAN_OR_EQUAL" etc ...
However if i start it in a few hours I can get it running for a considerable time again.
what cud be the problem? system overheating(the board has this CPU overheat protection), PSU problem, bad RAM ?
please help me out.

What have you done to your PC recently? sound like your RAM or your Processor problem. Try to replace the RAM see if it helps. Don't forget to refer to your motherboard guide books for the beep indication.

best of luck....

thats the point ... I havnt done anything to to it of late.
According to the manual, the beeps could mean
1) RAM not detected
2) CPU overheat, improper CPU/frequency setting
but that dos'nt explain why it works fine first and then goes beeping, does it? Besides the temperature software suggests CPU running at 55 degrees as always.
I'll try reseating the RAM like u suggest, but cant do that now ..am in office
Any more suggestions?

yeah ... even if you are in an office ... open PC and remove everything ... take ur figer ... wipe over the contacts and reinsert everything like it was before ... look especially on the Grafics card ... that this card is placed 100% correctly ... and .... clean the Northbridge fan !!!!

Take off the case and check all the fans, after that amount of time they'll probably be covered in dust, give em all a good cleaning and see if that fixes the problem.

Use aida32 or sisoft sandra 2003 to monitor the heat or you can just go into the bios and check the heat. What i meant by checking the tempreture is to run the program i mention and leave it there observe the tempreture and the tempreture just before it shutdown by it self. If it is over 60 then it is a good idea to do what chicken say try to clean up the heat sink for the processor and apply some thermo paste on it.

best of luck!

.. i meant i'm at work right now. And the PC thats affected is the one @ home. But thanks Mertsch, I think I'll do some cleaning once I get home. I did spot some dust (not a lot) on all the fans.
Hopefully one of these suggestions work ... I'd hate buying replacements for my cpu/ram now after all that saving I've done for a new gfx card.

does the thermo paste wear out after long use?
Sure will try this. Is motherboard monitor good enuf? I have that installed and I think it lets you log data too.

I think yes cause i am using volcano 7++ and it doesn't comes with any thermo paste or gel. I get the paste from my Geforce cooler (thermal take), and i try to apply some on the processor. after 2 months, i want to clean up everything in my PC, i take off all parts and perform the clean up but i notice that the paste decrease. If you are using the original cooler, I think it wear off slower or may be it can stand up to the processor life. Just check while you perform the clean up whether the paste is enough, but don't apply too much cause it will cause side effects.

I know this sounds silly but use shouldn't use thermal paste it spreads and evaporates after a while
:o
AMD installation guidelines

http://www.amd.com/us-en/assets/content_.../23986.pdf

shitshot are you sure about that?

I have tried less thermo paste on my Anthlon xp 2000+ as the result, the processor died

it sounds like a dying power supply to me...

Its a tricky one but last time i ever had a problem with my pc was when i had PC2100 ddr ram and what it did was a random BSOD (Blue Screen Of Death) everything u rebooted and started to load Windows XP or ran Installer it would do a random message, i had 3 x 256mb sticks and took each one out at a time and eventualy found out one was nakered so i had to replace it.

Thermal Paste does evaporate over time which is why AMD have stopped supporting it and only supply new thermal pads in the Retail Kits of CPU's all thou i know it evapourates i've never seemed to have any problems with it effecting CPU temp or CPU failing which is odd. hell i even used it on a old Slot 1 P3 and had no problems.

Check your Memory fella but i would strongly sudgest either changeing or just plain cleaning your CPU cooler, see if the Fan is runnun to slow, sounds like a heat problem

i agree with ThudZ3ro, a 300w PS for an Athlon XP 1800+ (which is what i have also) is not enough (read AMD specs). Probably not as effective now as it was when new & is killing ya! I went to a Enermax 450w PS. Great little item it is too.