I installed OpenSUSE on to an external harddrive forgetting to change anything about where it would boot from, so it wrote to the MBR and now I can't boot windows without having the external plugged in. My BIOS supports booting from the external, so I just want to change it to where I can boot linux from the external harddrive or boot windows without the external plugged in.

Install OpenSUSE's /boot on your primary hard drive maybe? I'm not sure if it would work though.

I would make a small 2 meg partition on my hd and install grub there, then you can boot your external hd by chainloading it.

Thanks for the help, but I also need to know how to fix it.

You could either install grub on the MBR of the internal drive, or simply repair the windows bootloader that was previously.

Boot your Windows DVD into rescue mode, and run the fixmbr utility.

Which version of windows do you have 'xp, vista'?

Do you have a windows dvd?

Do you want to use my suggestion above or use a grub cd to boot your external drive with evey time you use it?

I'm running xp. The 2 meg partition is a little unessecary in my case, and resizing the partition would take a long time, I'm not sure what I did before but what happened was I installed grub on the external, so if I didn't boot from the external windows just loaded up, but if I booted from the external grub would come up. With installing openSUSE I wasn't looking for an option to change where the bootloader would install to so I ended with my problem. Yes I have a recovery dvd and the install dvd, but I lost the key to that. Thanks for the help.

You need to use your xp cd as billymayday suggested and go into rescue mode and run the 'fixmbr' command. If that doesn't do it, you can try 'fixboot'. You've installed the stage1 of Grub to the mbr on your internal drive which wrote over the xp entry there so when you boot from the first drive, the stage1 is looking for stage2 and that is on the dis-connected external drive. Obviously won't work. Then you should re-install Grub and make sure you install to mbr on external drive. You could post the output of 'fdisk -l' command here and someone could give you detailed instructions.

fdisk /mbr or fdisk -mbr