Arcmap crashes on startup

Hi,

Am using Arcgis 10.1 Student edition. Suddenly when I start Arcmp it crashes with the option to report the error to ESRI.
I just finished uninstalling and reinstalling the whole thing again. Same issue. The license is Authorized.
It if helps, Catalog works fine.

Any help is will be greatly appreciated.

Sorry if there's already a thread on this. I could not find any by my search.

Thanks.