I did a full uninstall/reinstall as well and it worked fine. I could also get all missions to play except M3 after a series of hard resets and restores from backup. Heres my logic as to what happened...
Installed game right before work with no time to convert the key code over. Went to work and played the Demo missions a couple of times. When I finally typed in the code to unlock that night, I was asked if I wanted to play the first two missions again, I said sure.
D3 and M3 are different...maybe theres a thread still tying D3 to D2 after D2 has become M2?
If Im wrong Ill keep my night job
