Installed Ubuntu 64-bit now can't boot into either

[Mr Pockets151]

So I previously had XP and Mandriva dual booting on seperate hdds. Everything was good. Then I installed Ubuntu 32-bit on the same HD as Mandriva, but on a seperate partition. I installed the Ubuntu grub on the Ubuntu partition at step 7.

 

I configured my Mandriva menu.lst to boot all three OSs. Everything was fine. I did save my menu.lst

 

I decided to install Ubuntu 8.04 64-bit(as my system is fully capable) over the previous ubuntu install, however I didn't see the step 7 to install grub. So when it finished it reboot fine.

 

The old Mandriva GRUB still loads but I cannot boot neither Mandriva nor Ubuntu now. XP still boots fine. Anyway I can figure out what's wrong?