There's not much easy you can do about it, besides replacing it. In order to free it up you'd have to tear it completely apart, that would either ruin it or ya wouldn't be able to get it pressed back together again. I have one that's in a Hitachi that did the same thing, it was dragging and causing the disc to not spin. I have it freed up some now, but it's still nowhere near how a good one is.
About the only alternatives, and they're kind of extreme and may still not work, is to either dunk and run the thing in some type of cleaner that's not going to effect the electronics part, but clean out whatever gunk is causing the dragging. A good rubbing alcohol is one, not that 50% by volume stuff, it's half water. The other thing to do is spin the thing with an external source and see if it frees up. If you just spin it for a couple of minutes, by hand or whatever, it may work whatever's in there out and start acting right again, but that's a 50/50 shot really.