Download the Adobe Flash Player installer directly by right clicking the following link and selecting "Save link as".
Save the file to your Downloads folder.
Open your Control Panel and click Uninstall A Program under Programs and Features.
Uninstall the Flash Player plugin from the list.
Close the Control Panel, reboot and run the installer from your Downloads folder.
There is not a Flash Player Plugin in the list...
Should I attempt to continue the steps?
If Flash Player is not installed, then you should just go ahead and install it.
If you still get errors, please post the exact error message, as well as the contents of the FlashInstall.log file in C:\Windows\system32\Macromed\Flash