A friend of SWMBO's took round her parents ancient eMac - a single monitor mac from the early 90's. They'd tried to install Leopard on it (even though it was not supported) and borked it. So, my services were 'offered'.

The nice thing about Macs is that you can hold down the 'T' key when it starts up, and it'll act as an exernal firewire disk. A really handy way of getting user data off the machine should the O/S be screwed (as this one was). So once that's been copied onto a memory stick, its a case of seeing if I can recover the machine (but they're not that fussed, they're buying a new macbook in any case)..

One invaluable resource is the Mac bootup key reference here