I have a dell 4700 and the screen goes black after the windows logo, it only starts up in safe mode and it keeps saying that Multimedia video controller is not installed but I don't know what driver to install? I have ATI X300, what do I do?

Go here:

http://ati.amd.com/support/driver.html

and find a video driver for your system

I did but everytime I try to install it my computer freezes