Computer lags a lot when using more reasources

[SpiderWaffle]

I've got a C2D @ 2.8 Ghz, 2 gigs ram, 8800 GT, it's run fine for the last year. Lately it's been starting to lag more and more when it's under more use. Like having more than 3 web browser tabs, or running SC2, takes much longer to load programs after boot up. Takes forever to close SC2, then everything is very laggy and unresponsive afterwards. I got random bluescreen error once when my browser was frozen, I saw the word memory but it was only up like .5s and it couldn't give the diagnostic afterwards. It progressively been getting worse and worse. I have pretty decent virus protection and firewall.

I just checked the ram with memtest 3.8 today, did 5 passes with no errors.

MB is rather new, but could be fatly, or maybe it's the CPU.

What do you guys think?

 

[defaultluser]

Can you tell me one thing: is your CPU usage maxed-out at 100% when the machine is non-responsive? If so, it's possible that Windows has downgraded your storage driver from DMA to PIO (yea kids, even in the day and age of SATA AHCI, this is possible).

 

[Old Hippie]

Open the task manager and see what's running?

Check the event viewer for errors?

Run a free online virus scan from F-Secure or others?

 

[Shadowssong]

Possibly malware, I would run a malwarebytes scan.

 

[SpiderWaffle]

I really don't think it's malware, I run a pretty tight shift, and it never lags when I'm under light load.

SC2 lags it by far the most, and that program is designed to use all your resources, many OCers crash from it even though they don't under load testing. A few minutes after closing SC2 it's really laggy, but then gets better, and the longer I play SC2 the worse the lag gets.

I'm really thinking it's my processor now, I've had OCed pretty hard for most of it's 2 year life.