AutoCad LT 2013 on Windows 7 does not start

Hello, 

   My AutoCAD LT 2013 - English will not start. It tries to load, however, the process ends and the application never opens. 

I've tried 

reinstalling the application

repairing the application. 

renaming the auto desk folder under appdata, and having AutoCad create a brand new folder. 

System restore is not an option. 

I'm running windows 7. 

The software has run on this PC before, about 30 days ago. 

Thanks in advance.