Thanks for the replies.
I have Boot from CD as the first option in BIOS, when I restart the PC with the DVD in the drive it hangs looking to boot from the CD for a few seconds, and then goes on to load grub, showing a kernel on the hard disk. Just as if I had put a Rock Classics CD in the drive instead of Sabayon DVD....
Waitaminute, I think that's it, my PCs BIOS is set to boot from a CD as boot option 1, but I'm putting a DVD in the drive... do you think that's why it won't boot? Can't remember seeing an option to boot from a DVD in the BIOS options.
dammit. will have to wait till i get home and check this out.

At least it might be a clue, unless someone knows different.