registry problems with screensaver

[Brian23]

i just installed a program for my chemistry class called Chime. It change the file assosiations so that when I double click on an scr file, it tries to open it with internet explorer. I tried to uninstall Chime, but it won't uninstall, and now my screensaver wont work when i click on it. I know it has something to do with a registry key that was changed, but i don't know which one, or how to change it back. Please help.