Quite some time ago I installed Gentoo on my workstation for dual booting. As part of this process, I replaced the MBR installed by Windows Vista with GRUB. After getting another workstation for Gentoo, I decided to delete the dual-booting Linux partitions and recover the space for Vista to use. Sadly, I didn't stop to think before deleting my GRUB (/boot) partition and resizing my NTFS partition - rendering my system completely unbootable. I had to make the system bootable without rebooting, but how...?