Arduino Mega 2560 driver problem.


I have just reinstall my computer and did install Arduino 1.0.3 IDE. Witch i know work well.
Then the IDE wanted me to update to Arduino 1.5 witch I did. But what I forgot was that it mas up my Arduino Mega by install bad drivers.
So now I cant upload anything to it becuse i got the wrong driver install and I cant uninstall it because I cant find in under the Device Manager.
I tryd to manually install the Arduino 1.0.3 driver but Windows 7 don't want to install it.
How do i uninstall the driver for Arduino 1.5? Or update it when i cant find it. Its not even as an "Unknown device".

I have manage to install the Arduino 1.0.3 before but cant remember how I did it.