Just some thoughts: You have an older Mac, so that could be part of the problem. You may have processes running in the background, or perhaps your disk is too full. Look in the Apple Knowlege Base for things like Startup Items, Launch Daemons, etc and see if you have any that you can get rid of. Also check your HD available space. If it's too full, your files are probably fragmented and spread all over the disk, which might make it respond too slowly.