IE6 Stops Responding after 6 to 8 minutes

It's the most confounding thing I've seen. I'm running it on XP pro. When I boot up, IE works. The after 6 to 8 minutes, it stops connecting to the internet (If you click a page, I get "cannot find server or DNS error "). Other programs, like Outlook and Microsoft Money, can still connect to the internet. American Online for broadband can connect, but any link requiring an internet browser won't work. I've eliminated the firewall, and I've eliminated the router as a suspect. I've deleted and reinstalled IE6, and done the same with AOL 9.0. I've been trying to figure this out for three weeks now and the fact it always works after rebooting, but then stops after 6 to 8 minutes has me stumped. Any guesses?

 

I'll guess spyware.

 

I followed through on the tasks...

...but it still doesn't work after about 8 minutes. Did clear off some spyware, but no viruses or trojans. Was nice to know those resources are available on the web, so thanks. I currently run Norton's antivirus and firewall products.
Noticed today that while the browser stops working after about 8 minutes, I can access anything that has a "https:\\" or secure link. Tried about half a dozen of them, and they all worked. But in between these I'd try regular http:\\ sites and would get the same error message. Does this provide any clue? Something with DNS settings?
Also noticed when signing into to WindowsBBS right as the 8 minutes was expiring, I got a notice about how to deal with Zone Alarm. I had the Zone Alarm firewall on the computer for about a month, didn't like it, then removed it through the Windows Add/Remove programs. A month later, I noticed AOL didn't connect, and found other Zone Alarm files in various directories and manually deleted them. AOL then worked, but the 8-minute problem with IE started. Could there be hidden files I can't see still on the computer stopping things?

 

I guess I just answered my own question...

It was the Zone Alarm product. It didn't completely uninstall months ago. I downloaded another copy, turned it off so it wouldn't automatically load, and rebooted. The browsers been running for 25 minutes now, and I'll next try to uninstall it the right way.
Thanks for everyone's help.