Ubuntu Wubi Booting Problem

view story

http://askubuntu.com – i have a problem with my Ubuntu 12.04 Wubi installation, sometimes when booting, the computer will get to the purple screen without the Ubuntu logo, then will go to a black screen and then lots of white saccaged colors will appear and i will be taken to the login page. But sometimes, it just get stuck on the black screen and does nothing and i have to hard shutdown and retry it until it works. What may cause this problem and why? I can shutdown correctly. Thanks for helping. Edit: RADEON HD 7650M Graphic card with latest available Drivers on amd's driver download site (fglrx drivers caused sh (HowTos)