dual boot XP over Vista.. hal.dll corrupt


hey there,

Its been two days that i have been trying to get the answer of question. Now um posting it, I have Toshiba L350D with Windows Vista Basic as an initial OS. Now what I did without conulting anyone I installed windows XP on the Notebook, thinking that i would be able to use both of the operating systems together. XP was installed but the there was no option for selecting OS or no BOOT menu, then i manually edited the boot file from startup and recovery options as I could access the newly installed XP I was able to get the menu but now when i try the vista option it says Windows could not start becuase the <windows root>\system32\hal.dll is missing or corrupt. Please re install a copy.

Can any one suggest me the solution please.