Using Start -> Run, nothing happens. I typed iexplore.exe as you said. I also tried browsing for the I.E. executable in the Run box, found it, tried to start it, still nothing.
Someone told me Google Toolbar can cause this problem. But I checked and it's not installed on this computer.
I just disabled a third party firewall, thinking it might be interfering. No change.
Additional note: Windows seems to be running fine. And all other programs seem to be running fine: word processor, antivirus, instant messenger, windows media player, itunes, everything.
I won't be checking back here for several hours, but any suggestions i find when i return will be GREATLY APPRECIATED!