PSP UMD Problems. Can someone help?

My PSP 1000 is not reading discs. It was reading this morning, then it froze up while i was playing, so i restarted, but now its not reading. I got it used from a friend a few months ago, and he had barely played it. I have never dropped it, or anything of the sort, however i have been playing it almost nonstop since the new Final Fantasy came out. So can someone help me? The only thing i can figure is that the laser is dusty, considering it was in my friends car console for about a year.