I cannot get any browser to work for more than a few minutes without crashing. IE, Firefox, Safari, Minefield, 64 bit or otherwise. I have SP1 installed on my machine. Tried memtest and all good.
It could be DEP, but my guess is that one of the network dll's are corrupt. Check your event log and see if it mentions any system files. Run a CHKDSK and a sfc /scannow. If it is any browser it seems like its trying to use a bad system file.