Lukas Beeler's IT Blog

As part of a “security cleanup”, someone removed IIS from his Small Business Server 2000. The result was, well, obvious. Exchange stopped working. He reinstalled IIS, but Exchange still wasn’t working.

Luckily, Microsoft already knows what you have to do:
How to remove and to reinstall IIS on a computer that is running Exchange Server.

As usual, Microsoft KB entries aren’t very reassuring when it comes to “what data will i loose when i do this”. Don’t be concerned, reinstalling Exchange will not hurt your data in any way, if you follow the manual to the letter.