Windows 7: compaq presario cq56 laptop buzz and frozen issue

I am brand new to this forum and I may be mis-posting. I apologize if that is the case. I had my laptop plugged in and using it when I noticed it was fully charged so I unplugged it. I immediately got the buzzing and it's frozen. I cannot turn it off, do the Control Alt Delete thing, move the cursor, nothing. (I am writing this from my desktop unit.) It isn't overheating, thank god, but I am worried nonetheless. Probably will just let the battery die down, or should I remove it? Has this something to do with drivers? Or the fact that I updated Java this a.m. Can you tell I'm a computer idiot? Sorry. Thanks for any help you can offer.