Wireless Card Stops Responding - Certain Applications

Ive looked through the forums extensively and have yet to find a post with these similar symptoms.

On my Inspiron 6400, I connect to a Linksys WRT54g at home. I can stay connected for DAYS, if I use Firefox as my browser. I can also play online games without a problem.

However, if I use Internet Explorer, the WiFi LED above the keyboard goes out (bluetooth remains lit), the card software stops responding preventing me from reconnecting, and my only solution is to reboot in which it reconnects without a problem. Last night, I also discovered that when Im downloading songs from iTunes, the connection/card drops A LOT. It took 4 or 5 reboots to download 1 CD.

Ive had the wlan card replaced, under warranty. Ive tried numerous drivers from Dell. Ive tried several OS fixes (resetting TCP stack, flushing DNS, disabling IPv6, etc). Ive flashed the router to update to the latest release. Ive tried everything I know to try, other than format and reinstall and replacing the router...which is likely to be my next step unless someone has some ideas.

This began happening shortly, if not immediately, after I upgraded from XP to Vista Business, which was about 9 months ago. Any suggestions would be appreciated. Like I said, I can be connected for days, as long as I dont use IE, any program that uses the IE engine, or apparently, iTunes.

Inspiron 6400

Intel PRO/Wireless 3945ABG

Currently using windows to manage wireless

Vista Business SP1

Linksys WRT54g

WPA-2 Personal Security