I'm also having this problem, and I, too, have replaced the battery. My MBP is a 2008 refurbished body with 2009 hardware. Yours?
I hate it when I put the cursor into text and it doesn't stick!!!
Maybe the the springs? shocks? can be replaced? Other than that, we're looking at the magic mouse or magic trackpad, $69ea. Or, maybe there are off-brand equivalents.