4.3a not starting in Win7 64bit

I have a problem with the Comsol Multiphysics 4.3a.

I double-click the icon on the desktop, and the startup screen pops up. But after a few seconds, it closes down and nothing more happens.
I have run a memory scan with no problems showing. it is a clean install.

I run a laptop with windows 7 64bit with a intel iCore i3 processor and 4 GB ram. (Toshiba Satellite C660-220).