Internet Explorer disconnects after short time

I use a wireless card with a pci/pcmia adapter to connect to the internet on my Dell workstation. I connect then launch Explorer and surf for a few minutes and then Explorer closes on it's own and the desktop appears. I can launch Explorer again and the same thing happens. It seems to close after 5-6 minutes after launch. The connection (AT&T) however always seems to stay connected. I use Norton Internet Security (which is up to date) and the system was scanned with no problems detected. I downloaded Malwarebytes and ran a scan with the same result. This just came on in the last few days which makes me think it's a virus or something. Anybody got any ideas? Thanks

Did you recently upgrade to IE8? These kind of problems are almost always caused by problematic third party add-ons. Open control panel -> internet options -> advanced tab. Click RESET. If an option exists to delete personal settings choose it. Reset internet explorer and that will probably fix your issue. Don't forget to restart internet explorer after the reset.

FIXED with this solution. Thanks very much……