So I will try to be as specific and detailed as possible. I'm getting very lost hunting this problem down and I'm wondering if I'm missing something simple, or perhaps I've been compounding the problem as I went.
A few weeks ago I accidentally threw the breaker while my system was running (currently playing a 3d game - so my hard drive was likely reading or writing to the swap file my ram was on and cycling and my graphics card was engaged.)
Everything seemed to start up fine. I can't honestly remember what happend next, but shortly after I started having trouble getting the machine to boot - particularly after having it running for some time.
The system refused to post. I had to hard boot it to get it to post (power switch on psu off (press power) then power everything back on, and even then it only worked a quarter of the time. Once I had it up it worked though. Until I needed to reboot.
After reseating hardware and disconnecting drives and accessories and swapping ram slots I figured it was a memory error. It would run reliably with a single dimm in slot 1 (previously I had two in slot 1 and slot 3)
I bought some used ram off a local site and it seemed to fix the problem.
For a while.
Then I figured it might be a bad dimm slot (I could explain how I narrowed it down, but it seemed to work fine if I had ram in slots 2 and 4).
I did a pile of reading and evrything still seemed to point to the RAM even though I replaced it and had the system booting normally.
Then I got a virus (After I upgraded the ram I also decided to upgrade the bios and the downloader on the mfr website I think gave me a virus).
I reinstalled windows updated all my drivers and everything was working fine for about a week.
Then it died. It would boot windows to a blank screen with just a mouse pointer, nothing else. I tried repairing windows I tried reinstalling it and even during this process I would get blue screen errors. I thought maybe it was ram, maybe motherboard, maybe hard drive.
Anyway, Yesterday I went and got a new motherboard.
It posted fine with 2 Dimms, but not all 4.
I got a power supply alarm, and it didn't seem to matter which dimm I pulled either by slot or by stick. I wasn't sure what to think about that, so I got a new power supply just to rule that out.
Same weird error.
Suspicion shifted back to the ram.
I started going through it running 6 pass mem tests using win diagnostics.
I found 2 modules that tested faulty - one gave me the power supply error every time I put it in even by itself and another tested 3000 errors in the 6 passes.
Now I know 6 passes doesn't mean I have good ram, but it leads me to think that it isn't the problem.
So with new motherbaord new power supply and new hard drive partition (ruling out bad physical space on the drive [but not read/write errors] I proceeded to rebuild the computer and run windows)
Everything was great. Multiple reboots all posted fine BIOS settings were correct controllers and hardware detected and installed properly. No viruses. Disk checks all passed and I had a working computer.
I then put the old power supply in and moved the computer into it's home.
I played on it for hours last night.
I rebooted it even for good measure.
Everything worked great until today.
I booted to three consecutive blue screen errors.
All three were different.
And I can't for the life of me remember what they were. I'll post more details later if I can get it to error again.
Anyway I kept posting fine and booting to bluescreen in windows.
I finally rebooted into a memory test and one of the modules failed like 39000 failures in 2 passes.
I hard booted again and everything came up fine again.
I ran some checks and everything looks great again.
I cannot figure out what is causing the instability.
Is it hard drive? Still suspect memory?
I am pretty sure one of the dimms on my other motherboard was faulty, but I can't prove that for sure, but there is still something else wrong here.
Thoughts? Ideas? Other tests I can run? This computer was running stably no overclocking for 3 years, and now I can't get it to go a couple of days.
I want to return the motherbaord and power supply if neither of those is the issue.
Please help. Specs to follow.
CPU: Core 2 Duo E6550 2.33 Ghz
RAM (old): 2 x 1 GB crucial pc6400
RAM (new): 4x1 GB crucial balistix 1066 2.2v
Current RAM 2x1 GB balistics 2x1 BG pc6400 (yes I know I'm sacrificing speed, two of the balistics modules tested bad)
Motherboard (old): ASUS P5K premium black pearl edition (I love this motherbaord and hope nothign is wrong with it - warranty expired 3 months ago)
Motherbaord (new): Gigabyte S series P43 ES3G
Graphics card: Asus Nvidia 8500 GT silent
Internal card reader
Sata LG dvd burner
IDE DVD rom
2x 250 GB caviar hard drives
Antec sonata 3 case.