This all started a few days ago with a power outage. After the interuption, I turned my G4 MDD off & then back on - I got to the grey screen with apple & the spinning "hash-marked" wheel. It sat there for a while & then I got the black screen telling me things weren't o.k. in several languages - what I now understand is the kernel-panic screen. Anyhow, I replaced the PRAM Battery. I know I paid too much but I needed to get the machine back up & running - $20 @ Radioshack for a Tandon 3.6 volt 1/2-AA Battery TL-5902 (Enercel is the R.S. house brand). I also found 1 bad stick of Ram. I replaced the main HDD that the OS was installed on with another HDD - wiped it, partitioned it & installed Tiger. Things seem to be fine now.