When I start up my computer it turns on fine, but when it goes to start up the OS I get this message...
"Windows could not start because the following file is missing or corrupted: <Windows root>\system32\hal.dll.
HAL is an acronym for hardware abstraction layer. The hal.dll file is a Windows NT file that is used by windows when communicating with your computer's hardware. It enables hardware from different vendors to allow them to accept a common set of Windows commands. If it is missing Windows will not function.
In situations where it has become damaged, either from virus activity or hardware failure, it may be necessary to replace it with an undamaged copy. Here are the steps necessary to replace the hal.dll file with an undamaged copy from the Windows CD:
As above, insert and boot from your Windows XP CD.
When you receive the "Press any key to boot from CD" message, press a key to start your computer from the Windows XP CD-ROM.
When you receive the "Welcome to Setup" message, press R to start the Recovery Console.
Press the number that corresponds to the correct location for the installation of Windows you want to repair, typically this will be #1.
At the command prompt type: expand d:\i386\hal.dl_ c:\windows\system32\hal.dll. (where d: is the drive letter of your CD and c:\windows is the location for your Windows installation folder.) If prompted for permission to overwrite an existing version of the hal.dll file select yes.
Once you have expanded the file type "exit" to exit the Recovery Console and restart the computer.