Dave Gutteridge dave@tokyocomedy.com wrote:
How can I reinstall Windows with a clean partition, and preserve my dual booting?
Recommendation #1:
Always use your Linux Rescue Disk to boot and re-install GRUB afterwards.
Recommendation #2:
dd can be used to preserve and return the _full_ MBR. I.e., the _full_ MBR is Cylinder 0, 1 cyl * X heads * Y sectors * 512 bytes/sector
So if your disk geometry is 16/63 heads/sectors, to preserve the 512KiB MBR: dd if=/dev/XdX of=./MBR.dd bs=512K count=1 to restore the 512KiB MBR: dd if=./MBR.dd of=/dev/XdX bs=512K count=1 conv=notrunc
If your disk geometry is 255/63 heads/sectors, to preserve the 8MiB MBR: dd if=/dev/XdX of=./MBR8MiB.dd bs=8M count =1 to restore the 8MiB MBR: dd if=./MBR.dd of=/dev/XdX bs=8M count=1 conv=notrunc
Gotcha A: This will _also_ include the disk label (partition table), So it _only_ works when it's a matching replacement.
Gotcha B: Some service packs and hotfixes for Windows NT5.1 (XP) have been stealthy using portion of the MBR for disk geometry and other information. This sometimes _breaks_ GRUB and other boot loaders as they step on each other.