Recently I had to repair windows xp due to some errors. But after the repair i found that i'm unable to log in to Debian because Grub boot loader is missing and instead grub windows boot loader has activated. I did some research and found out following process.
1: sudo grub
Then grub> will appear
1: find /boot/grub/stage1
The reply was (hd0, 8) so i had to use them as parameters in later commands
1: root (hd0,8)
2: setup (hd0)
3: quit
Easy as that .. that did solve my problem