FS9.1 "already installed"

Have been troubleshooting my sim for the past 3 days after an FSDT scenery was giving me registration problems and I had to do a reinstall /twice/ since I could not get the thing to even load at one point.

The first time I uninstalled FS9, reinstalled it, then uninstalled 9.1 and then reinstalled it again to make sure it was done right. I had to uninstall fs9 again because of an issue with the nocd patch, so it wouldn't even load, or if it did, it would load the splash and then quit.

The second time I uninstalled fs9.1 /before/ I uninstalled fs9, and now when I try to actually install fs9.1, the system tells me it's "already installed" and will quit.

That's not what such FSDT scenery is telling me (tells me I need 9.1 and that I'm using some old .dll for fs9.0). I don't have the uninstaller available on the fs9 directory so I either do something either more complicated and break the simulator again, or I try to do it the right way.

Thoughts? What should've been a 10-minute problem has swelled into a major a headache. Thanks!

Aaaaaaaaaaaaaaaand I found the answer. Frankly I'm upset I did not try this earlier as I had seen it mentioned on another forum but... am stubborn. So much time burnt..

Just remove/delete the BACKUP folder in the flight simulator directory and that somehow does the trick. I had a hard time finding explicit answers for my troubles so at least now it's in plain english: "fs9.1 already installed" when it ain't simply means delete the dang BACKUP folder!!