Try and follow this, Adobe Flash Player just got installed and worked in my vista PC:
Windows Vista installation failure
On some Windows Vista systems Flash Player may be installed, but will not display Flash content. In some cases updating to the latest Flash Player using the included utility can correct the User Account Control settings that cause this problem.
To run the utility, find your installed Flash folder:
The letter changes with each Flash version, so may be "FlashUtilb.exe" or "FlashUtile.exe"
•Select "Run as Administrator"
•Follow the steps to complete the Flash Player installation
•Restart your computer