Let's see if the steps will still work to recover the System MBR into Windows 7.
Download and burn to CD free Partition Wizard bootable CD
. Boot PW, allow files to load, select 1 for Screen Res, rightclick System Reserved partition to Delete, OK. Next rightclick Windows 7 partition>Modify>Set to Active, OK.
Now right click Windows 7 partition again, select Resize, drag left border over deleted System Reserved space to include in Windows 7 partiiton, OK. Apply all steps.
After PW reboots to finish resizing, boot into Windows 7 DVD Repair console or Repair CD, click throught to Recov Tools list to run Startup Repair up to 3 separate times with reboots to recover System MBR into Windows 7.
After Windows 7 starts, Add XP using EasyBCD 2.0. Accept boot files, autocompletes, restart.