Someone in the comments to this thread said the bug has been fixed
Thursday February 5th, 2004
A serious bug in the latest Windows installer builds of the Mozilla Application Suite can lead to users having the entire contents of their Program Files folder deleted. The problem is present in the 2004-02-03-18 and later trunk Windows installer and net installer builds. The affected binaries have had the suffix -dangerous added to their filenames and been removed from the latest-trunk and latest directories on the mozilla.org FTP site. Testers are strongly advised not to download these dangerous builds. The issue is being tracked in bug 233014 (please do not add unnecessary comments to this bug). Thanks to Zbigniew Braniecki for alerting us to this problem.