gtk problems

The basic problem I'm having is that I deleted Pidgin, gtk, and aspell from my usb drive and tried to reinstall. I can't reinstall gtk because I guess the computer thinks that it's already there (didn't use the Add/Delete menu because Pidgin was installed on my usb drive and shouldn't be on that menu anyway.) I've tried using a registry cleaner, and I have no recent restore points. I suppose I could reinstall gtk, but the version packaged with Pidgin seemes to be slightly old and a bit harder to find. Any help, please?