I'm using WinXP SP3. This problem occurs with both firefox and internet explorer, so I don't think it's a browser ISSUE necessarily.
When I watched video online (hulu, youtube, etc) after a few minutes the video gets jammed and the audio starts skipping, repeating the same noise over and over. Even if i close the browser, the noise persists. After a few seconds the computer gets jammed all together (mouse moves, but no buttons are active, alt-ctrl-del doesnt work). i have to manually shut down and restart.

I've updated graphics and video drivers, scanned for viruses (nothing). I have no IDEA what is causing this. Could it be hardware? RAM maybe? Is there a way to check for these problems?What are your system specs?2.16 GHz with 2gb ramOkay. Open TASK Manager to the Processes Tab and sort on the cpu COLUMN with highest usage at the top (double-click on "cpu"). Play a video. when the problem begins, see if some process is chewing up your cycles.With all applications closed I saw the following:

System Idle Process: 80-90
Services.exe: 10-20
System: 0-5

At point of "death", with firefox and video running (then getting jammed):

System Idle Process: 45
Firefox.exe: 30
Services.exe: 22
System: 4What type of internet connection is this ? ?I know you said you scanned for viruses, but I'd do it again. I don't like the services.exe process using so much of the cpu. Use BOTH your av AND MalwareBytes to scan PLEASE.