Hi, It may be helpful if you read over this troubleshooting guide by Adobe.
If you decide to Uninstall and Install again, I would use the "executable" which you can download to your Desktop.
Have you previously installed any beta version? I'm sure you know you need to use the 32bit browser since Flash Player
is not supported on the 64bit.
The Anti-Virus/Firewall, Security Settings for IE, Permission requirement are important. Also the necessity of Rebooting twice after the Uninstall for IE, to make sure old files are removed.
If you have any questions, just post back.