Laptop series: Vaio VGN-CR11GH/R
OS: Originally Vista Aero home basic.

Condition:
1. Installed xp to a different partitioned disk different from Vista's disk.
2. Xp works well, but apparently the laptop drivers accept only Vista.
3. Trying to run Vista instead, after the OS selection screen (before loading screen) it showed "File lost or corrupted [/windows/system32/hal.dll]" and the laptop restrarted afterwards, and continuously failed to proceed.
4. Checked on the windows vista directory (yeah this time I log on with xp) the file exists in the directory shown.
5. Tried to overwrite with the hal.dll from xp (crazy? sorry I'm desperate already) failed. It shows (file [vista's one] is protected or is currently in use.

Qs:
1. If I fix the hal.dll file, will my vista work normally again?
2. How can I fix the hal.dll file, noting that I can't be overwritten by normal means. Where can I get it?
3. What's the alternative to fix this problem?

-The drivers work only with Vista.

Thank you!