What is the exact error message that you are getting? (the wording is important)
You say "I deleted it and downloaded it again to no avail" but have you used the Adobe uninstaller to cleanly and completely remove Flash before you reinstall it? http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html
You haven't mentioned what operating system you're using but if you're using IE on anything less than Windows 8 then you are using plugin based Flash for both IE and FireFox so you can try Google Chrome which uses Pepper based Flash (like IE on Windows 8) which is compiled into the browser rather than run as a plugin and that may overcome whatever problem you are having.
- Norm