I'm not sure if this is going to be of any help to you, but I don't believe you can actually remove / delete an MBR from any disk. You can, however, overwrite it. Select the program that you would like to use: Windows loader, GRUB, LILO, etc. and follow the instruction that came with it to install it to the MBR.
As for resizing / changing partitions: try qtparted that comes with Knoppix. Wonderful tool, I use it all the time.
HTH.