Unless you're curious what the actual problem is, it might be time to try re-installing the OS. Get the Combo updater for OS X 10.6.8 and re-apply it. This won't disturb your user files, and may correct whatever is wrong with Finder. (It won't hurt to back up everything first. For that matter, it wouldn't hurt to have a backup, period.)
As much as I dislike the nuclear option, I think gangbustein is right on with this suggestion. You could easily spend hours or even days working on this issue and never solve it, or you can reinstall the OS so you can go on about your business. As gangbuster said it will not change any of your data or settings.
