Un-install again. Look for the installation file of Dell Support Center, make a right click on the file and go to properties. Choose on compatibility tab then choose under compatibility mode. 
When I upgraded to Windows 8, Dell Support Center stopped working. It worked in Windows 7.  When I reinstalled the software, the messages says that it is up to date.  My Dell opens, but I get the error message: "My Dell has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available."  I haven't had any other problems with the Windows 8 upgrade.  Any ideas about how to get Dell Support Center to work?  Thanks.
Dell Support Center Crashes in Windows 8