To back-up your mail folders in Outlook, click file, and export. Then select export to a file and click next. Then click personal folder file and just follow the rest of the steps in the wizard - it's dead easy. You can then import it back later.

I suppose ideally un-installing then re-installing would be the best thing to do (as is could be one of these "goodies" that's causing the problem) but if your can't be arsed, I suppose just re-installing over your original files may do the trick. If at any point you get the chance to "repair" your old installation - take it.

Internet Explorer is on your XP Pro disk. You may have to run Windows update in order to get it back up to version 6 and then install the service pack.