Vista Randomly freezes

I have a Gateway GM5478 PC I bought it back in September 08 it's nice and all but for the last couple of months Vista has been randomly freezing it doesn't matter what I am doing I could be sitting at the desktop and decide hey I want to surf the net or play a game. And somewhere along the line of doing that it'll freeze up. Mouse still works, but can't get to task manager and if I do I get a black screen and Failur - Security Options. So I figured it was malware maybe one got through despite all my efforts right? So I ran my full suite of anti malware scanners (Spybot, Avast, Malwarebytes, Spyware Terminator, Superanti) and they all came up clean, so I figured it was overheating so I downloaded and installed CoreTemp to monitor the temperatures, none ever go above the limit and don't come close to the temp limit. So I figured maybe I need to defrag (at this point I was getting desparate) so I started a defrag which is in progress now.

I personally believe that I have a memory fault but when I run Memtest I ran in boot mode, clean. I ran in Vista, both were done overnight the Vista scan itself was clean. I even ran four copies (Because I have a Quad Core machine and thats what Memtest advised I do so I did) and told them to scan whatever memory wasn't in use. I ran Windows Memory Diagnostics Tool but it froze 21% through a extended test however I was able to exit out it and let the computer finish loading Vista.

On a particular note my model PC shipped with a annoying BIOS glitch, something to do with the event timing for fan detection, that causes it to hard restart the PC every hour, on the hour, usually several times during the day and then it mysteriously stops. It was hard to confirm because it may only do this one or two days a month and the days are completely random, however I plan on upgrading the BIOS I just want to get a UPS and a spare motherboard I even Identified the driver I need for BIOS. The BIOS problem is what made me think of getting CoreTemp as I thought the restarts were caused by high temperature. It seems thats not the case.

The random freezes only started a couple of months ago otherwise, except for the BIOS glitch, my computer ran like a Ferrari. I take very good care of it to the best of my ability and money supply (which isn't much). So I feel like I have failed or something, can somebody give me some advice on how to proceed with troubleshooting? I thought Gateway included a hardware diagnostic toolset for system hardware but I see they didn't so. I also checked my HDD both with HD Tune and with the diagnostic program for my Western Digital HDD, I did an extended test with the WD HDD utility and it too was clean.

 

I think you need to check what's been happening with your PC by scanning through the System logs looking for errors etc.. Right-click (My) Computer > Manage > System Tools > Event viewer and highlight System. Then go up to View > Filter and check Critical, Warning and Error. You could save the log as a .evt file, zip it and upload it for someone to check over if you like.

Temporarily disable everything running under Task Scheduler or go through them all to see if any are reporting errors, failing to start, etc..

My understanding of Memtest was that it should be run from a bootable CD for something like 7+ full runs for more thorough testing.

 

I checked Event Viewer. System has nothing from the time the freezes occur and Administrator Events only contains "The system restart at [insert time here] was unexpected." Which doesn't help because I already know the restart was unexpected I did it myself.

When I ran Memtest in boot mode it was from a DVD I created, it was clean. When I ran it within Vista, it was clean. Both ran for about 10 hours (overnight and during the time I spent trying to put my head together (Because I had just woke up and I do a terrible job at it.)