Go Start>Run (Start Search in Vista), type in:
msconfig
Click OK (hit Enter in Vista).
Click on Startup tab.
Click Disable all
Click Services tab.
Put checkmark in Hide all Microsoft services
Click Disable all.
Click OK.
Restart computer in Normal Mode.
NOTE. If you use different firewall, than Windows firewall, turn Windows firewall on, just for this test, since your regular firewall won't be running.
If you use Windows firewall, you're fine.
Same problem?