The telephone scam is becoming very common - They probably got your numer from facebook or the telephone directory.
If you let them take control of your PC, you should probably reformat and reinstall, and notify any financial companies you've dealt with on that computer about potential identity theft.
As for your computer problem - the reformat and reinsall will probably cure that - or you could post about it with a LOT more detail in the more appropriate Windows Answers forums,at
http://answers.microsoft.com/en-us/windows/forum/windows_7-system?tab=unanswered&page=1
Noel Paton | Nil Carborundum Illegitemi |
CrashFixPC | The Three-toed Sloth