My idiot brother in law decided to install OS 8.5 on my moms computer and now when you turn it on it freezes on the loading screen. I think it does this because it is an old system and doesn't meet the system requirements. And when I try to reinstall the original OS it won't let me. Is there anything I can do to avoid starting the os 8.5 and instead install the original OS?

First of all, figure out what Mac it is and how much RAM it has, and let us know... p

It won't let you hold down the key to force it to boot from the cd? That is weird. If it's so old that it doesn't have a cd-rom drive, it won't let you stick the floppy in when the chime sounds? If it spits it out, put it back in right away and it should work. Of course if the disk is hosed, you might have to make a new set. Apple has posted a whole catalog of classic OS's for free download on it's website. All the way up to 7.5.5, as I recall. I made backups of systems I've never even used. One never knows...