How does it behave if you boot to
Safe Mode with Networking? If better then something is starting at boot that is causing the problem.
Advanced startup options - XPAdvanced startup options - VistaAdvanced startup options - Windows 7Use msconfig to determine what is causing the problemThese are good tutorials on using msconfig in XP, Vista or Windows 7:
How to use msconfig in Windows XPHow to use msconfig in Windows VistaHow to use msconfig in Windows 7Click on
Start then
Run, type
msconfig and press
Enter.
Click on the
Startup tab, record what is currently starting then click the
Disable All button.
Reboot and see if it runs better.
If yes then use msconfig to enable several items at a time till you find the culprit.
If no, start msconfig and click on the
Services tab.
Check the
Hide All Microsoft Services box, record what is currently starting then click the
Disable All button.
Again, do a regular boot, see if it runs normal.
If yes then use msconfig to enable services till you find the culprit.
Once you've found the culprit, uninstall it or find out how to eliminate it from your system. Simply disabling it in msconfig is a temporary fix at best.
Enable everything else you disabled.