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!