I too have this problem that only manifested itself a couple months ago.

I’ve been running vista ultimate for over a year now with no major problems until a couple months ago when both IE7 and Firefox spontaneously stop working after a while. I know I still have an internet connection because AIM still works and torrents continue to download, but all browsers come up with an error. Another machine running vista ultimate connected to the same router hasn’t shown this issue though. The funny thing is, when the problem started nothing had changed in my machine. No new programs installed, no updates from Microsoft, no new hardware. The only thing that fixes it is a system reboot. There is no error in event viewer that I can trace to this problem.

I do a lot of computer hardware research and built this machine myself so I have in depth knowledge of all the hardware inside, drivers installed, and programs on the system. I’m an electrical design engineer and programmer so I’m no stranger to debugging. Yet this problem has me completely baffled. I agree with magmatrix that this problem doesn’t seem to be any of those things he listed. If anybody figures out anything, please post your solution on this site.

Kemical,
Magmatrix posted all those things it is not to help prevent others from wasting time going down dead ends. Be happy you’ve never run into a problem you couldn’t solve or find someone else’s solution to. Remember, not everyone can be as lucky as you.