My rig is:
-Asus A8V-X board
-1,5 GB RAM (2x0,5 + 2x.25)
-2 x HDD (120GB healthy Samsung + 250 Seagate with fixed (a few) Bad Sectors)
-Radeon 3850 AGP/ Radeon 9800 PRO
-Win XP SP3 + Win 7 Ult
-constant in-game crashes, ocassionally crashing during network browsing
-as a result the system was reinstalled
No problems then for a few months...
And suddenly, new symptoms:
-often crash in win, unable to load winxp/7 in normal mode (the was a small chance it could run properly, but it could then BSOD during internet browsing)
-stable work in "safe mode"
My verdict: faulty VGA, because:
-removing/cleaning all catalyst drivers also gave stable system (but laggish)
-trying change RAM combination (up to using only one module...) doesn't bring sufficent changes
-processor (and VGA) wasn't overheating (tested by special software) - it could BSON even when computer was lost unsused (only OS turned on)
-HDD 120 was for XP, it should work (no bad sectors)
So, I changed 3850 Radeon to good old 9800PRO... and guest what?
-it worked stable for a few weeks
-my brother install Starcraft and it started restarting and BSODing!
-unsitalling starcraft helped for 2 weeks
-now computer returned to occasionally restarts
PC was given to the service, it could not help so far (?!), coputer was given back with note "error wasn't reporduced easly so it could not be fixed"
First update your anti-virus (or install one - AVG, MSE, Avast) and run a full scan. Then download and run malwarebytes. Always the first thing to check when getting wierd things happening. Let us know if that helped or, if not, and we'll help.
might be the power supply as well. Seems like it is slowly getting weaker and all the things you've done have decreased the load/idle power consumption.
Do you have a spare one or a friend whose psu you could borrow to test with?