Mac not booting, Invalid memory address

Hello,

Hoping someone might be able to help with this mac problem a friend of mine has. Personally I don't have a lot of experience with macs but I work with pc's so hopefully some of that should apply here. When you turn the mac on, a few seconds after the sound it plays I'm presented with this screen:


Invalid memory access at

&SRR0: ff848580 &SRR1: 00003030

Apple Powerbook 6,5 4.8.7f1 BootROM built on 09/23/04 at 16:13:38

Copyright 1994-2004 Apple Computer, Inc. All rights reserved.

Welcome to open firmware, the system time and date is: 01:04:41 02/09/1904

The battery capacity is: 88 percent

To continue booting, type "mac-boot" and press return.

To shut down, type "shut-down" and press return.

ok
0>_

I've coloured the & symbols red because I couldn't make out if they were actually & symbols or % symbols.

Googling the error comes up with nothing at all. If I type mac-boot the screen goes grey for a short while then the mac turns off, and strangely doesn't seem to want to turn on again for a while. Even removing the battery and putting it back in and then pressing the power button doesn't seem to get it powering on again, I have to leave it and forget about it for a bit, then pressing the power button gets it turning on.

I'm guessing this is a hardware fault but not sure what. Obviously the data and time is wrong so perhaps the cmos battery is dead (don't even know if macs have a cmos system or battery to be honest but they must have something similar) but I wouldn't think that would prevent booting. I have the tools to open it and am perfectly comfortable doing that.

Can anyone suggest anything?

Thanks.