When I found a thread on google groops about a power macintosh 5500 freezing, I thought I was finally going to fix my stupid 5500/250. I ordered a new Rayovac Alkaline 4.5v battery and installed that. I got the whole way through the MacOS 9 installation. Then the damn thing does the same freezing crap. Quite annoying. If anybody reads this and has a solution - please email me and tell me how to fix this thing.