Winxp win7 dual boot

ok.. so i had winxp on c-drive and win7 on second harddrive d-drive, and it dual boot was fine ,got a virus somehow and had to reformatt c-drive,,,,,,,,i disconnected the d-drive win7........and reformatted c-drive winxp, i reconnected d-drive win7 still on there,,but os only reconizes winxp,,anyway to get i,t to see win7 on d-drive so it dual boots again,without reinstalling win7 again ,i know there is only winxp in the boot ini..thanks....