Give this a go,

when the window appears for the exception, look for any other messages that can help us...

reseat your memory modules in your pc, make sure that you ground yourself if you have not got an anti static strap...

If the problem persists, while using the net, shut down all applications and running processes in the sys tray. Leave the connection to the net and if your ISP puts its icon in the sys tray then leave that running to, there should be only your connection in the sys tray otherwise...

Use your internet as normal does the problem still persist...
run scandisk and scanreg in dos mode for good measure to keep your system in tip top condition...

keep us posted on the B.S. (Blue Screen)

Jase