Turn off anti virus then reboot, see if it works
Run an antivirus scan and download and run malwarebytes. http://www.malwarebytes.org/mbam.php
If this is a new problem, you can just to a system restore
from before the problem
If you did an upgrade to get windows 7, do nothing, just tell me. An upgrade does not require that you reinstall your programs.
If you did a clean install, try this http://www.sevenforums.com/tutorials/3413-repair-install.html?ltr=R
But I would just download from here: http://windows.microsoft.com/en-us/w...nalize/gadgets
Make a system restore point first.