Try this......
Switch on the computer, and keep jabbing at the F8 key periodically (but don't hold it down).
Eventually, you will see some choices come up - choose "Use last known good settings".
If that fails, do the same again, and choose "Safe Mode", which loads minimal drivers. If this works, you should see Windows open in a lower resolution format, with the words "Safe Mode" in the corners. If this happens, close Windows again, and see if it starts normally now.
If neither of these things happen, you will need to find your original Windows install disk, and choose "Repair" when it starts up.
P.S. Looks like the culprit could be
Windows Live - see
http://www.help2go.com/forum/computer-help/102599-reboot-loop-3.htmlGo into Safe Mode and uninstall it.