Windows 7 recognize HD but windows xp cannot

[Dorpet]

I have on same HD-500GB win7 and win xp. I conect another HD-320GB in sata drive. Bios recognize both HD, win 7 too, but win xp recognize only HD-500GB. When I go to disk manager in win xp it's same problem I only see one HD-500GB. Please help me.