It sounds like you're having issues with permissions on your computer. The reason you couldn't open IE and the reason the programs couldn't open it are probably the same. I would go to the root directory of IE and take ownership of the .exe. Hopefully that'll help. If it doesn't, try disabling UAC to see if that fixes it. If you don't want to keep UAC disabled, switch to Firefox?
Lost connection and double posted due to FF error, see below for more.