random freeze while streaming online video

[kensai]

My home built computer has been having random crashes since August, but before then it worked fine. Historically, the crashes have happened in various situations, changing with each attempt to fix them. The most recent change I made to my system was to get rid of Norton Internet Security and replace it with Microsoft Security Essentials. Since then the crashes have become a bit more reproducible: about half the time I try to watch streaming video online the screen will freeze and the sound will stutter, requiring a hard reset.

I have run windows memory diagnostic, prime95, and various graphics card stress tests repeatedly, so I feel I can confidently say the problem is not hardware. Besides, this only started a few months ago, and my computer had been working just fine for a few months before then. Any suggestions?

 

[kensai]

Ok, seriously, anyone?

My computer has also been crashing randomly when it is left idle for a long time. Sometimes I leave it on all day (I have it set not to go to sleep, but it does turn off the display) and I come home to find that neither the keyboard nor mouse respond, and I have to do a hard reset. Suggestions?

 

[TheLeadingEdge]

If you are sure its not hardware and it only started happening in August and it was operating just fine prior to August, it implies a software issue of some point where the OS or some application software was updated or installed/re-installed (given also that the video playback issue was NOT accessing the internet or other outside-your-box resources), then I recommend going back to a restore point just prior to the August time frame as first step. You can troubleshoot from there to pinpoint the issue. If going back to a restore point does not fix the issue, then the assumptions of good hardware and not using outside resources such as network/internet need to be re-evaluated.