I had Windows 7 installed all september. But I installed Windows XP Professional back because my computer couldn't handle the new OS.

After first boot I tried to install newest flash player (from Adobe website), but it failed. I had my old setup on USB drive and it worked. I don't know is it important or not.

I am watching Youtube videos in my free time (almost every hour). After few days the computer started to freeze when I open a page with the video or close the page with video, not while I watch a video. No BSODs. Nothing in Event viewer. I use Firefox only.

When computer freezes the sound wont. If iTunes is playing a radio station or is it another video playing in background, the sound wont freeze.

Last few days the mouse wont freeze. Its a strange symptom. If I click few times then the cursor will actually freeze.

I just want to know where does this problem come from (hardware - graphics card, old motherboard or it's just some glitch in setups). If it's not graphics card then I will be happy. The graphics card is ATI Radeon HD 4650 - brand new.

Catalyst 11.8 installed.

Things I have tried:

• Installed newest flash player after a week (the setup didn't fail this time)
• Installed latest video drivers
• Deleting cookies
• Defragmenting hard drive
• Using TuneUp utilities for computer cleenup
• Installed latest Mozilla Firefox
• Cleaned the PC
• Changed CPU Fan speed almost to max (just to be sure)

Things I haven't tried yet:

• Didn't try playing videos on other browsers

What can I do now?