Vista keeps freezing

Hi,
I came here as I keep having trouble with my cousins pc.
It keeps freezing after any period of time, no set time like others, and I thought it may of been virus/malware related when speaking to him on the phone, so I offered to have a look @ it.
I have run a2 squared, malwarebytes, and ms security essentials and all have found nothing.
I have also run ccleaner which did clean up a lot of garbage but still the problem persists.
I have done just about everything I can think of including, removing pci cards (video, tv tuner, dial up modem), checked the ram with memory test, and only run the pc with 1 of its 2 sticks @ a time and then swapped still no difference.
I have also swapped the mouse, keyboard and am running my own monitor, with no change.
It can happen at any time, from opening an internet explorer page, to opening the control panel window, to looking in the event viewer, or simply running any scans, and the network cable doesn't necessarily have to be connected either.
I have tried to interpret the event log but cant seem to find a lead there except error messages stating that "the previous system shutdown was unexpected." and "ms security essentials failed to update". I have updated vista but that hasnt helped either, and also updated the nvidia chipset drivers which include things like Ethernet Driver, SMU Driver, SATAIDE Driver, SATARAID Driver, RAIDTOOL Application, SMBus Driver, Installer 5.68_a GPU Driver.
The computer is an acer aspire m5640 with intel 2 duo core, 2.4ghz with 2gb ram, 230gb sata hdd (with approx 20gb used), running vista home premium 32bit which came preinstalled with no cd.
I hope someone can help. If you need more info, just ask I will do my best to get it for you because Im @ a loss now.

 

Hi Plodr
Well I tried the program you mentioned but the PC only froze once with a entry being red. That entry was dllhost.exe. You mentioned heat being a problem, the hdd seemed warm to touch and i installed crystal disk info and that reported the hdd getting to 48deg Celsius @ one stage but not it didn't freeze. Im trying again now with process exp to see if anything happens with a couple of virus scanners running at the same time to see what happens.

 

well i thought i would try safe mode today as others who had similar problems didnt seem to have the problem there.
So i started in safe mode with networking, and the problem still happened.
I looked for the folder options to turn off thumbnail preview but couldnt see the options it described?
I will restart in normal mode to see if that is why.

 

Hi
I found the thumbnail view in folder options and turned off thumbnail view but the problem still persisted.
Im still @ a loss. Maybe its time to send it in for a professional to look @ either the hdd, power supply of motherbaord as they are really the only other things I cant really test.
Not unless someone can think of something else quite obvious.

 

Have you done a chkdsk?

http://www.vistax64.com/tutorials/67612-check-disk-chkdsk.html