installing a bootable Debian without grup touching other drives in PC

[Rolf Blum <rolfblum@ewe.net>]

hallo,

after trying to install a dual boot system grub destroyed two times my 
bootdisk. I have a lmdb-4 on a bootable usb-stick. The Live version runs 
just fine on my PC. My goal is to have a drive which will boot Debian 
when I select it in the win-boot-menue. What have I todo to prevent grub 
from touching any other drive and just install on the drive reserved for 
Debian? I am not experience with Linux, please help.

Kind regards