it sounds like it might have lost the activation for the game. or its being blocked from the internet to check itself when it launches
if it worked recently please try doing a system restore to a day when it was still working ( instructions below) If that doesnt help or it looks complicated i am able to log in remotely and get you my phone number to sort it out for you on your computer as we talk
System restore instructions - windows 7 or 8 8.1
hold the windows logo key down and hit R
type rstrui.exe in the run box that comes up and hit enter
select restore to an earlier date.
Under the "suggested restore" which is usually not old enough to help is a link for "OTHER RESTORE POINTS"
click that if the suggested ones are not BEFORE THE PROBLEM STARTED
choose a date that is BEFORE you experienced the problem
hit ok / restore
the computer will start to shut down
a restoring settngs box will appear with a status bar
when it finishes your computer will restart with the same settings it had on the date you restored to. your data will not be affected.
It is not perfect. But it fixes a lot of things.