Can't Drag and Drop?

I saw an old forum post about this issue, but I couldn't find any real solutions so I'm posting again.

I am using a MacBook, not MacBook Pro, purchased in January 2011. It was working totally fine until I updated something in January of this year, and then I found I couldn't drag and drop. When I drag anything with my mouse, it looks fine until I go to drop it. Whatever I'm trying to move simply won't drop. It started with just picture files on my browser (I use Chrome), but now it happens with all my applications.

I checked my extensions folder, but it was empty, and deleting all the .kext I could find on my hard drive did absolutely nothing. If I use the three-finger option to drag, I still experience the same problem.

I'm currently running Mac OS X 10.6.8.

Does anyone have a solution for me? It's making my laptop frustratingly hard to use.