was up all night trying to figure out the same thing, finally came up with a
solution from one of the messages and it worked for me, so i'l copy paste it to
this message-

I filled in the support form on adobe's website and they were very helpful.
They emailed back, and after making sure that I had no old copies of flash
player told me to go to http://www.adobe.com/go/full_flashplayer_win_msi where
I could download the installer. It seems to be working now

Yes! Thank you so much for this! I've been having the problem for a while where
I had flash, but whenever there was a flash detection on a website with
Internet Explorer it would tell me I did not have flash (it worked in Firefox),
and whenever I tried to install flash again it gave me the '' problem. Then I
uninstalled everything, went into the registry and deleted all Flash player
files, and still no luck. This finally fixed it. Thank you again.