Thank you for your reply. And now the details:
Yes, I am dual booting. But for years, I've used two separate hard drives for Windows and Linux. This way if one OS dies, I still have the other that can be used (usually, but not this time because of dead GRUB). I did choose this time, installing GRUB in it's Linux MBR section. The first attempt, I chose the /boot sector, but that was bad also. Since I'm using the GUI installer, I have no way to see what operation is happening when GRUB gets installed by the Installer program. This is the way that I've done with the latest versions of other OS's, without any problems, with GRUB2. But this time, I did see a message that menu.?? was missing. However when I put the live DVD in the broken machine (DVD drive still works, and boots up), I still found and saw menu.?? was there, and it had a link pointing to grub.conf . But it also told me that Grub.conf, doesn't exist. Funny, I couldn't see Grub.conf in the Konsole terminal, but I did find it when I used a GUI file manager. It was a binary file. Not that easy to read or make heads or tails out of it. I tried to install a new version of Grub, in the installed Sabayon drive, but that failed. Also, this time when I ran the "live" version, it didn't automatically mount and display the box's hard drives on the desktop. This made it harder to see which designation that Grub had assigned each drive. I finally spotted the Windows drive, and the Linux drive was designated as "%". That was not very helpful. With my setup, I'm not messing with Windows at all (this is the same way that I did with my laptop). With the laptop, Grub, got installed on an external 320GB USB hard drive's MBR. It manages the menu to choose between Windows or Linux. If I unplug the USB hard drive, then Windows boots up normally, with no Grub needed to get it started.
My only conclusion, is that Grub is corrupt. And I don't know that much about the underpinnings of Grub to take it to the limit of good operation. I would be interested in taking GRUB from another distro that I know works. But I need step-by-step to do this. And, evidently, the way that you had installed GRUB was with a single hard drive with Windows living on it. I didn't go that route. I love to keep 2 OS's separate!
I hope that this clarifies some things. I highly appreciate your come-back. Now, where do we go from here? If I can't succeed, I'll have no choice but to dump Sabayon, even though I like it very much, for another distro that can handle a graphic installation. The prior working version of Sabayon, didn't present this kind of problem. It was installed the exact same way as this newest version. I expected no problems with the latest version of Sabayon, considering that it should have been much better than the older version that I intended to replace.
I currently run the latest version of PCLinuxOS in the laptop. Grub was totally installed by the OS's GUI installation program. No intervention on my part. No special deviations to get it running. The installer took care of the whole thing. Oh, I don't have a Windows installation disk. Vendors are too cheap in our days. They install a Windows factory version on a separate partition of the Windows hard drive. And that setup basically is designed to install the whole OS if the previous version went bad.