Please begin a new thread when you have a new question. The only reason I'm answering you is that you added yourself at the end of a thread I've joined earlier
http://www.linuxmint.com/forum/viewtopic.php?t=852
As for your mouse I don't know but suspect it could be the case. It can't hurt you to follow the advice in the thread. If it doesn't help change back..
Don't fix it if it ain't broken, don't break it if you can't fix it