I have Windows Vista and Linux Mint 12 KDE installed on my PC, each installed on it's own hard drive. 

I recently wanted to try out Windows 8 Consumer Preview and see how it ran on my PC so I created a partition on my Windows hard drive for Win 8. After installing Win 8, GRUB no longer appeared when I turned on my computer, but a Windows 8 bootloader that let me choose between Windows Vista or Windows 8. 

Well after testing out Windows 8 a bit, and trying to get it to detect my wireless adapter (outdated drivers), I wanted to use Linux so in Vista I wiped the partition that had Win 8 installed and reallocated the memory for Vista.

When I started my computer it still tried to use the Windows 8 bootloader and had all sorts of errors, and would automatically restart the computer over and over again. I almost had a heart attack that my computer was unusable, but after booting from the Win 8 CD I was able to boot into Vista, and in System Configuration removed the 'Windows 8' boot option which set 'Windows Vista' as default. 

Great, now my computer boots, but where is GRUB? How can do I use GRUB again to access my Linux distro on my other hard drive?