This is by special request of my son....
This is actually very easy if you have a few things in place first.
1. You must be able to view hidden folders.
To view hidden folders you may need to open my computer and go to the "Tools Menu" and select "Folder Options" then select the "View Tab". From the list of view options enable view hidden files and folders.
2. You need to have a cd for Windows XP with same service pack level as what is installed on your system. This step is precautionary to make sure you have the right IE build. If you have a cd but the wrong version you might try searching the web using the term "slipstreaming".
Ok now that we have that out of the way...
Put you operating sytem disc in the cd drive and cancel out of the autorun menu that pops up if it does.
Open "My Computer" and navigate to the "c:windowsinf folder".
Look through the list for "IE.inf" and right-click on the file. Select "Install" from the context menu.
The istaller will start and if it immediately can't find iexplore.ex_ it will ask you where it is. So just browse to it on the cdrom drive i386 folder and click ok....reinstallation begins.