Do a clean boot: http://www.toughadmin.com/slideshow.php?article=Cleaning&i=2
If that doesn't do it for you do the following:
1. Go to Start, click Run and execute regedit
2. Navigate to HKEY_CURRENT_USER\Control Panel\Desktop
3. Look in the right panel for AutoEndTasks and change it to 1
4. Look in the right panel for WaitToKillAppTimeout and change it to 1000
5. Reboot (you will still get the error if you don't reboot) and then try it out.