Repairing my MBR

[<res0nid7@verizon.net>]

Hi,
My machine has the Lindows(linspire) linux system as well 
as debian sarge.  I was booting through the Grub menu that 
Sarge setup and had CHmodded the jiffyboot program in Lindows
 to prevent it writing to the MBR, which it does every time it 
is rebooting. Somehow, however it did do it and so I now have 
a Lilo boot for lindows only.  My Sarge install is intact but 
I can't get at it.

Is there a way to boot into Lindows, chroot to Sarge and rerun 
the Grub MBR write so that I can get my Grub menu back?  (If 
there is please provide clear instructions :)  I'm a noob!!


Thanks,

Jim