It's possible MSO was "loaded" onto the machine by neutralizing some basic functionality, and the process went awry. I would try a System Restore to a point previous to MSO. It's available at Control Panel / System / system protection. If it doesn't open, try booting into Safe Mode first.
Also, go to Control Panel / User accounts and verify that you are still an admin.
If System Restore doesn't work, and if you can open programs in Safe Mode, I would use the "tweaking.com" program to reset file and registry permissions, to re-register services and reset them to their default opening states, and to restore some other basic functionality.
Create a Restore Point first, in case something goes awry, then go through it systematically, including the disk check and the SFC. Note that SFC may not work in Safe Mode, so you may have to try it in full mode. (There are other options if you can't do that - see
http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html)
If that doesn't work, you can do a Repair Install, or a factory recovery or full reinstall. The last two options will delete your data.
NOTE: At this point it would be an excellent idea to first make sure your data is safely backed up anyway. If that's not already done it may mean pulling the drive and attaching it to another machine via USB adapter.