this is a copy and paste of the tail-end of a whole other problem. To recap: LC-575 (circa 1994), bought from school surplus, OS 7.5/7.6.1, CD & floppy. I'm desperately trying to do a clean install of OS 7.6.1. Pardon my lazyiness: I still can't do a clean OS install, but I'm pretty sure that my problem is "on guard" (its icon looks like two little fencing foils when the extensions parade during startup, right?). This would explain why I can't disable extensions with shift, and why I can't access the HD, even from a boot disk. I've already been eagerly searching a few "hackintosh" sites, looking for a way around this extension (including opt-command-s, using "find file" to find the "on guard" preference folder) but nothing works so far--I still can't disable extensions and the folders are made invisible to me in "find file." One of the more promising things I've come across is "no guard," an emergency password generator made from the cracked algorithm. Another (much scarier looking) solution is to use resedit, which I don't think I even have, to get down into the nitty gritty. Plan of action? Anyone?