If you installed XP to a second partition to Windows 7, then it requires adding it to boot menu using EasyBCD 2.0 Add/Remove tab:
Dual Boot Installation with Windows 7 and XP
However, EasyBCD requires Net Framework 2.0 to run from XP, so you are better off adding XP now from Windows 7 anyway, since you recovered the MBR back to Windows 7 from XP.
Install EasyBCD 2.0 after doing quick registration to use beta, Add XP, accept offered boot files, Save, restart to Dual Boot Menu.
If you have any problems, please post back a screenshot of your full Disk Management drive map, using Snipping Tool in Start Menu, attach file using paper clip in reply box. Include the front panel listings from EasyBCD