constant crashing...

Does anyone know why ever since the last update to the flash player I have been constantly crashing? And I mean CONSTANTLY!! Once it starts crashing it keeps doing it until it freezes my PC..I have uninstalled it, reinstalled it, and it was fine for 6 days and then started doing it again tonight. Uninstalled again..reinstalled again...but it gets so bad I can't even shut down my PC properly. I am running Mozilla Firefox (up to date) on Windows 7...Help!!