[stakanov]

Do you WANT to remove the grub because you want to restore the XP MBR (master boot record) or do you want to install OpenSUSE on the new disk and restore the original dual boot?

If it is the first it is as follows.
Assumptions:
-your pc has a dvd/cd and can boot from it.
-you want to restore the MBR of XP to be able to return to the original status.
-you have a working install CD
Procedure:
Boot from the XP install CD.
The setup programm will understand there is a bootable XP partiton available.
On the first screen appearing you will press "R"
On the next screen you will press "K" to trigger the "recovery console".
Now you type the command: "fixmbr"
If for whatever reason this should not work you can try to use the command "fixboot c:"
This recreates completely the boot sector in the first partition (although it should not be necessary).

Note: the commands are to be written without the "". I.e. "do" you have to type do

Hope that helps.

Ps. OpenSUSE can be easily installed with less hassle if you use a separate /boot root and /home partiton. So in case you xperiment a bit too much you will not loose valuable data.