Problem solved, although I'm unsure of exact cause, since I did a number of other software installs between succeeding FF installs. But I have 2 most likely suspects. The particular PC I'm using was salvaged from another department in my company after being hit with a virus that was quite severe and the dept admins just decided to replace it. While installing other software, I got an error about the replacement PC having the same name in the company domain as this salvage one, although MS-IE-8 ran OK under that condition (now fixed). Also, while uninstalling FF, I had left a console CD'd to the FF run directory so as to add the safe mode option, and the uninstall program never mentioned that it couldn't delete some FF-related files, it just didn't delete them. It wasn't until I went to manually delete them with Win-Explorer that I got a non-deletable message. For the duplicate machine name problem, it wouldn't be proper to ask you folks at Mozilla to try to detect it, but for the non-deletable file problem, I would recommend that you provide some type of warning message in the uninstall program when some program files can't be deleted. - Dennis McNulty, Portland, OR, USA