I am running WIn XP Pro and it is set not to reboot, and the error is DRIVER_IRQL_NOT_LESS_OR_EQUAL.
I am not using any kind of router. I have Norton SystemWorks and Internet Security and run scans all the time.
I have cable and this only happens when I'm downloading at high speeds off mIRC.
Yesterday I downloaded mIRC 2.14 and it seems to be pretty stable. I was downloading 3 files each over 100 kbs and I didn't reboot once. I don't know if the new version fixed things or not but I'll keep trying to reproduce the reboot again to test for sure if the new version fixed things.
Thanks for all your help!