Dual boot problem for Vista / Xp, already installed the both.

I have already installed both Xp & Vista on two drives with dual boot. Both were working fine with dual boot menu.
But for learning purpose i have used Hiren’s Boot CD. After using PC config tool from Hiren bootCD it hangs during that & on restart, its gone!, the dual boot menu.After that on repairing with Xp CD it loads only Xp with “no boot menu” & then by Vista DVD i have tried via bootrec.exe & set the “ntldr”. Now after these the dual boot menu is available but,it only loads Vista. On selecting Xp it gives error as,
File : \ntldr
status: 0xc000000f
Info: The selected entry could not be loaded because the application is missing or corrupt.
What’s now. Pl. give the solution.
thanks for reading.