Did you try running the Adobe cleaner tool?
If you were a participant in the pre-release program you shold have access to a tool there, otherwise, try Resolve installation problems with CS5 Cleaner Tool
And in future, NEVER run beta software on a mission critical machine. You need to be prepared to completely rebuild any machine that you use for testing, and one really good method is to make a disk image of some known good state that you can restore if necessary so you don't have to go through the hassle of reinstalling the the OS and all the apps, but it's still a pain.
You might, if the cleaner tool fails, try using Windows System Restore to go back to a point before you installed the beta software, but the odds of that working after everything else are probably not better than 50-50.
I did use the cleaner after i found out about it but unfortunetly it was too late. The adobe programs sitll dissapear.
I was too late for the restore part. If i am right the restore didn't have a choice to go that far back.
Well, I guess this is a lesson learned about beta testing...
Back up your data and as much of your user profile as you can, collect your disks and get ready to format and reinstall everything.