Unity keeps crashing!!!

I have been using unity for about a year and only now has it started to crash, after I have been on it for about 2 minutes it freezes up and I have to use task manager to end it because windows cant make a good computer which has a working X button!!! Can anyone help me?

I had this exact thing happening to me. Are you running the newest version of Unity? When ever I updated it fixed itself, also what operating system are you using? If you hit play the game runs and then if you stop it and hit play again does it freeze up as well? That was another thing mine happened to do.

64bit-Windows7 Professional