Did you totally take it off? In my computer it's in "Program Files" then" "Internet Explorer" and the actual program is called "iexplore.exe". If you find it there you could click on it, and it should run. It may say, "this is not your default viewer, would you like to make it your default viewer?" And just click "yes."
Your other option is to download it again. It will probably make it you default viewer. What kind of operating system do you have?
Try clicking on this:
http://www.microsoft.com/nz/windows/internet-explorer/