If you are running short of time before you meet the deadline and have to turn in your computer, best would be to format your computer and reinstall whatever Operating System you wish to use.
If not, you may wish to uninstall and then reinstall Internet Explorer. If you attempt do so, use a program such as Regseeker to clean your registry to make sure that reinstalling your browser will have a better chance of working.
What exactly is Yahoo DSL?
http://www.snapfiles.com/get/regseeker.html - Regseeker - Freeware
Or you can look into another browser. Mozilla Firefox for example. This will NOT replace Internet Explorer, it will function on it's own.
You can also set Firefox to function as your standard browser.
I donot know if this will please your employer. You can, however, use this as a temporary solution until you can get your original browser repaired.
Or completely forget about Internet Explorer and move on with Firefox. It is much more user friendly.
http://texturizer.net/firefox/ - Firefox - Freeware