Can't click with usb mouse or trackpad buttons

Ok, this is a really bizarre problem. I installed Ubuntu 9.10 about a month ago, and everything has worked great. But a couple days ago, the buttons on my wireless usb mouse stopped working. I'd click various things but nothing would happen. Brand new batteries, and I was able to move the cursor.

Also, it would only be like this in certain applications. For example, the first time it only wouldn't click in Firefox, but I was able to click the Ubuntu menus and such. Then it evolved to the point where I couldn't click those menus either.

It used to be sporattic. It would stop working, then fix itself after a while. But now every time I boot up into Ubuntu, I can hardly do anything, because once I launch an application (any application), the clicks stop working.

Any idea what the heck is going on?

It could be that the mouse drivers got messed up, you could (if you have a spare wired mouse) reconnect the mouse from scratch, i have found that ubuntu 9.10 is much more friendly with bluetooth mice, so if this doesn't work, I would reccomend backing up and re-installing.

Would screwed up drivers explain why my laptop's built-in mouse doesn't work either? It's the same story with that: I can move with the track pad but can't click.

Quick update: the problem seems to be intermittent. The mice (the built-in and usb) clicks were working completely, then stopped. Now they're working again. Rebooting does not seem to be a way to temporarily fix it, as there was one instance where it didn't work right after startup.