How can I remove GRUB and restore Windows XP boot.?

I installed "Ubuntu 10.10" onto a new and completely empty internal hard drive and have "Windows XP 2000 Professional" on a separate drive. Ubuntu installed "GRUB" into the system and all was well until the drive containing Ubuntu failed completely after about 1 month, (It was brand new and I'll be chasing a refund or replacement) As the new drive is no longer functioning or connected when I attempt to start my computer Windows will not boot and I get the GRUB message "No such device - grub rescue". The only way I can now boot Windows is to use a boot disc (Paragon Backup & Recovery Media, works exceptionally well) and have it locate the Windows O/S and boot it. Is there any way I can remove GRUB and restore the MBR to it's former state so things can go back to normal? To further complicate the situation I DO NOT have a Windows Disc. I did try "System Restore" to see it could go back to before the installation, but it runs into problems and fails for some reason. If there is a solution to my dilemma could you please supply some fairly comprehensive directions as I get a little apprehensive about playing around in this area of the system. Any help or suggestions will be greatly appreciated.