If you previously installed a newer version of Flash Player for Firefox, you can avoid installing an earlier version. For example, if you installed Flash Player 9,0,115,0, and tried to install version 9,0,47,0 the installation would fail. To resolve this problem, download the uninstaller for Flash Player from "How to uninstall the Adobe Flash Player plug-in and ActiveX control.
1. Click Start> Run.
2. Type cmd in the Open box and press Enter.
3. In the command window, type the following:
Note: uninstall_flash_player.exe file should be stored in the same directory as the command window is in (eg C: \).