Black screen after 7.10 fresh install, No Grub!

[siulca]

After many fruitless tries at getting the 8.04 upgrade working, I decided to go back to 7.10.

In an attempt to keep my data and configuration, I installed 7.10 on the root partition without formating the /home partition. The installation went fine but on boot Grub didn't load, leaving me staring at a completely black screen. And to make matters worse, after this I couldn't even load from 7.10 Live CD (yes with CD-Rom selected as the first boot device in the BIOS).

After much head scratching I managed to boot from the Live CD by either physically removing the hard drive from my machine or by selecting a USB drive as the primary drive in the BIOS boot settings.

Booting from the Live CD I re-installed Grub to the both the MBR and the partition but the same problem persisted.

So I decided to backup my data, completely format the drive and install 7.10 from scratch while letting the installer to partition automatically.

Well, after rebooting I still got the same greeting, a black screen freeze with no grub nor error message.

My guess is that the MBR is corrupt? But I don't understand how Ubuntu would damage it! Nor do I know how to restore it!

I read half of the internet this weekend trying to fix this problem, tried a load of possible solutions even thought I can't find the exact same problem anywhere.

Now I ran out of ideas, so please please please tell me you have a fix.


Ty.