did you use the text installer or the graphical installer.
there is another post around here about the text installer putting "no-x" in the grub confighttp://forum.sabayon.org/viewtopic.php?f=86&t=19561
read this and if this is your problem then you can fix it, but if it's not your problem then you need to tell us some more info on the install and your box. maybe you might have errors in your log files, you might have a bad md5sum, you might have burnt is at to fast of a speed. have a quick search around the forums and see if others have the same problems.http://forum.sabayon.org/viewtopic.php?f=86&t=16505
this is a good place to start and learn about sabayon. I also suggest our wiki and IRC.