Yes, if you have some spare time, you can investigate.
Do this...
Go Start>Run (Start Search in Vista), type in:
msconfig
Click OK (hit Enter in Vista).
Click on Startup tab.
Click Disable all
IMPORTANT! In case of laptop, make sure, you do NOT disable any keyboard, or touchpad entries.
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.
Assuming, everything runs nicely with the above settings, go back to "msconfig" and start enabling services and startups, you just disabled, BUT one by one, restarting computer each time, until you'll find a culprit, which slows things down.
Good luck and keep me posted.