are you updating from an old version a flash? What browser and operating system are you on?
Yes, I am updating from an older version. I am using IE 8 on windows7.
I know you said you've tried everything, so forgive me if you've already tried this.
1. Uninstall flash player as described here. Remember to delete the four folders described in step 3. If you aren't using a 64bit windows machine you can ignore deleting C:\Windows\SysWOW64\Macromed\Flash folder. it won't be there.
2. download this zip, extract it.
3. Navigate into the 11_7_r700_202 folder. (not the debug)
4. Install flashplayer11_7r700_202_win.exe and flashplayer11_7r700_202_winax.exe
5. Once they are installed verify that your flash player is working by going here.