Randomly Freezing

Hello, ive tried in a lot of forums to explain and get help but no answers or partial one only. My pc is randomly freezing in Windows 7 Ultimate. From startup, after loading screen where i am able to see desktop and taskbar...the taskbar is freezed. For making the pc works, i have to ctrl+alt+delete and cancel or esc. It is really annoying.

Ive read in some threads from here, each person which different solution. I dont see how should that Process Manager or how its called, help me, because i dont have any idea what to see, how to use it. Ive disabled everything from startup in msconfig, tried a lot of stuffs, Event Viewer...and still same.

A very weird thing is when i enter in World Of Warcraft or any other game, it freeze more, damn annoying. Can you help me somehow? Steps or something..please.

I suspect the Ati Radeon video driver, but im not sure. And please dont beging with scanning with malweare, antivirus and so on, /sfc scannow etc, just dont, i tried that already, twice !!

PS: If i select from msconfig Diagnostic Startup, everything works great.

Is there any way we can find out more about your computer specs and what type of anti-virus and malware scans you have performed?

Pentium Dual Core E5200 @ 2.50 GHz, 4 GB Ram, Ati Radeon HD 4800 Series

Ive tried Avira ANtirivus, Malwarebytes' Anti-Malware, CCleaner, Tuneup Utilities, SUPERAntiSpyware, etc.

Ok thanks Jerry4fr00z.
I'm not familiar with TuneUp Utilities but I trust all the others. I doubt there is a nasty on your system.

One last question (I hope). Was this an upgrade to W7, a clean install or a new (brand) computer?

It is probably video card issue.

It was from Vista to Windows 7, i only formatted C: