eratic macbook
Recently my macbook has been acting eratically, the cursor is jumping here there and everywhere (when I'm not even touching the computer) and clicking on programs, playing music, highlighting text and images, right clicking and editing information... the list goes on. It is impossible to use. Just over a week ago, a friend used their USB in it which was around the time it stared to refused to copy and paste from internet to word documents. I am wondering if it has a virus or something? and what I can do considering it is so crazy. My macbook is almost 2yrs old and all software is up to date, with regualr iAntivirus running. Any ideas?
MacBook, Mac OS X (10.6.8)