Issue with OS X [urgent]

Quite the Mac noob, so just wanted to help =]

Basicly after updating "Transmission" my iMac sort of froze. Allowing you to move windows and use the dock but not enter text in text areas.

I rebooted, this time the the dock loaded, the top area disapeared then the dock crashed.

I rebooted a number of times, wanting to uninstall Transmission but wouldnt allow me to. Sometimes I would get error messages saying Finder and the Dock had crashed.

I then booted OS X, in safe mode. The dock didnt crash and the top was there. but didnt allow me to access anything. I couldnt launch time machine or any other app, not even Finder.

Please help!

 

Please help, this is quite urgent