|It all depends on exactly what you did. Without knowing that I assume it has tried to go back to IE6 but that is missing too.|
In which case, on another machine download IE7 or IE8 (depending on which you prefer) from MS on the web. Either burn the download to a CD or put it on a flash drive, then transfer it to the computer with the problem and double click the downloaded file.
How to know you are getting old 1:
If you can remember when radishes tasted of something