Just did a 2 day recording session in logic, I havent backed up yet, and my powerbook appears to have died. It wont start up normally, not even with the software restore dvd. I get the following message when trying to startup:

Invalid memory access at
%srr0:000101cf %srr1:0101cff4
to continue booting type "mac-boot"
to shutdown type "shut-down"

when I try to continue booting nothing happens, it stays on the first screen with the apple and the little circle going round and round forever. It never gets to the blue os x progress bar. any suggestions would be much appreciated. I have days and days of work on this hard drive.