Can I move MBR to different hard drive?

Hi all i am running a dual boot setup i have XP on one HD and 7 on the other, it seems that the MBR is installed on the HD which has XP installed on it as i found out when i unplugged it 7 would not boot up!! I am looking to remove the HD with XP as I dont use it, can i move the MBR to the HD with 7 on?

hope you can help

Craney

Yes, first mark Win7 active in XP Disk Management, or using free Partition Wizard bootable CD.

Next unplug XP HD, boot into Win7 DVD Repair console or Repair CD, click through to Recovery Tools list to run Startup Repair up to 3 separate times with reboots to write the MBR to Win7.

Good question. You can change the active OS in XP by modifying boot.ini as explained here:
How to edit the Boot.ini file in Windows XP
However for 7, you can use bcdedit command line or try the easybcd tool that was made for vista, I don't know if it works on 7 or not if they have a new version:
Download EasyBCD 1.7.2 - NeoSmart Technologies

cool cheers for that, it does seem to be 7 that is the active OS as this is what it boots into if i do not choose, so would the best way to do it be unplug the hd with XP boot up the 7 dvd and reapir the MBR that way?

I do have the easy BCD installed on the xp hd but not to sure on how to use it

thanks again

You should do as Gregrocker suggests and mark the Win 7 partition or the Win 7 System Reserved partition (if you have one) active. Then disconnect the XP drive...

What happens? If it won't boot, run the startup repair, as suggested.