I've upgrade my Ubuntu 12.10 to 13.04. I dunno what happend while updating, but I've lost the Launcher bar and header bar. and when I opened the Terminal I've not seen the three buttons ( mini, max and exit ).
Seems your Unity interface is broken. Are you using any proprietary drivers? NVIDIA/ATI etc? Those seem to have a spitefull history with X and Unity...Anyways, try running the below: