Here is how to do it:

• To run the program, go to Start>All Programs>Accessories>System Tools>System Restore
• Select the "Restore my computer to an earlier time" radio button and click Next
  
• Click on a date on the calendar that is prior to your install of SP2 and click Next
• Read the warning message on this next screen screen and click Next
• You will have to reboot your computer after the wizard finishes and your computer will be rid of SP2 and unfortunately, any other program you might have installed between right now and the Restore Point you selected.
  

Hope this helps! I have done it many times when my mo-sheen starts acting buggy and a reboot doesn't seem to fix it.

Cheers!
Bill