You should NOT have to unclock it each time. There should be a setting that will disable overclocking when you start the computer in the BIOS. All OCing programs that I know have to be enabled everytime you start, and have to be enabled again when you restart the computer, that is a safety feature so you dont forget about it. My BIOS just crashed so I couldn't check it for you lol.
Doing this on the college computer.
"Just because I'm sitting between you idiots doesn't mean I want to go skiing!"