my unity crashes! help

hi guys. right the problem is that when i try to run unity windows says that unity editor has stopped working and no matter what i do i can not get it to run.

I am running a 64bit windows 7 machine and i have reinstalled the program (6 times!!!) and i have also fiddled with compatibility settings i dont know what to do.

i am running the latest version of unity.

i have contacted unity with an email and a bug report and all they can say is thank you for the error report. ok please help when i first ran it on my machine it worked so can anybody tell me it wont work now.