Booting Windows when early boot fails

So this was my problem; an old laptop wouldn't boot Windows XP. After the Grub menu, I would just get a black screen with a blinking cursor when choosing Windows XP. Other installed OSes worked fine.

Ntldr, Ntdetect and boot.ini were all fine. Reinstalling the MBR (running fixmbr or fdisk /mbr, deleting Grub) or running Windows repair would not fix it. Also the boot flag was set.

Turns out the partition itself, not just the disk, has a boot sector, this was probably corrupt. I got it to boot by using Grub, and replacing the line "chainloader +1" with "ntldr /ntldr" in the menu entry. This skips the boot sector on the partition and loads ntldr directly. Wehey, it booted!