The trackpad button on my 2007 Macbook Pro seems to be sticking. Specifically, it's stuck in the "down" position, which means I'm selecting pretty much everything all the time (you wouldn't believe how frustrating it was just to ask this question). It was fine yesterday. What can I do to unstick it?
The trackpad getting stuck is also a well known symptom of a bulging battery in the MacBook Pros of this generation. I'm dealing with this issue myself and am very annoyed about it too, because this 2007 Santa Rosa MBP I paid for is essentially the most lemon computer I've ever owned (at least four other hardware failures besides this one).
This is going to sound dumb, but have you restarted the Mac? I've had this issue on my Magic Trackpad a couple of times and the only way I was able to cure it was with a simple restart. (At first I thought it might be because I also ran MagicPrefs, but I've since removed that and the problem still occurs sometimes).
If you find a restart 'fixes' it, as I have done in the past, then it's possible that it's the software getting confused rather than a physical issue. I haven't found a Terminal invocation yet to restart the mouse driver part of the Mac but I reckon that if I found one I could probably use that to unstick the pad when the problem arises.
In most models there's a screw directly beneath the trackpad that influences how hard/soft the click should be. If you have the right tools to open it up, you could try turning it a bit to see what happens.
What you can try first is to press down on the button, hold it down, move your finger from left to right a few times and then let it go again. Sometimes this fixes it, but if somethings really broken or worn it probably won't work.