Problems with Finder & Safari

[twoeyesinajar]

This just started yesterday. I can open finder by double-clicking anywhere on the Desktop, the hard-drive icon that appears on the Desktop by default will suddenly disappear when clicked on it, I cannot move any file to the trash by dragging, command-deleting, or clicking "Move to Trash" because Finder will restart. When I click on the Safari icon, it takes much longer than usual to appear and when it does it always stops responding and I have to Force Quit it. Fortunately I installed Firefox some time ago, so that is what I'm using. I did a virus scan last night, and that did not fix the problem. I also have problems with World of Warcraft -- sometimes I can terrible lag, or it suddenly freezes, and just today my Cosmos add-on seems to have reset itself. I am using a Powerbook G5 which I purchased summer of last year, with 1GB of RAM.