Lost MBR in partition, Vista won't boot

Hi, very simple thing happened. I created a 3rd partition which meant I then acquired the hidden disk recovery, one partition with Vista and another with Windows 7 Beta, then I created 50 gigs for Windows XP Sp3. I'm not sure why windows xp took over my boot from the original OS's, but it pretty much crippled my system because I wasn't able to get online and get something that would alter the drives (or don't know how to do it). I deleted the Win XP partition with the Win XP CD, but out of sheer hope, but that as anticipated took out my boots. Now I cant get into the drive. Is there anyway I can get my boot loader going without a reformat using Dos or something? I have two other computers handy, but I need my main one back.

I was thinking of installing Vista CD on the 3rd partition, then download EasyBCD (name) and then using that program to alter the boot process. Possible? That would be two Vista's installed on 2 drives, but its the only way I can think of doing it

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