Installing Adobe Air 3.9.0.1380

My computer won't install Adobe Air 3.9.0.  At one point, it wouldn't uninstall Adobe Air version 1 and I had to purge the registry as well as its folder on the 'C' drive before I could get rid of it.  But every attempt at installing the latest version throws up an error message suggesting the install might not be allowed by the administrator.  I am the administrator, and I have no trouble with any other program and there are no restrictions set that I know of.  Can anyone please help me find a solution to this problem?