Try this..

For Vista (32 bit):

1. Open Computer.
2. Navigate to C:\Windows\System32\.
3. Scroll down and open the Macromed directory.
4. Open the Flash directory.
5. Right-click FlashUtil9b.
6. Select Run as Administrator.
7. When the UAC prompt appears, select Continue.
8. Follow the Flash Player installation wizard.

For Vista (64 bit):

1. Open Computer.
2. Navigate to C:\Windows\SysWOW64\.
3. Scroll down and open the Macromed directory.
4. Open the Flash directory.
5. Right-click FlashUtil9b.
6. Select Run as Administrator.
7. When the UAC prompt appears, select Continue.
8. Follow the Flash Player installation wizard.

Enjoy!