Repairing windows root system 32 hal dll. in a dual boot drive.

Hi I've recently tried to create a dual boot drive on my inspiron 1545 laptop. I have two primary partitions one with xp installed the other windows 7. I installed them oldest first as that was what the internet/instruction manual said to do. When I just had xp running it worked fine, so I installed windows 7 on a sperate partition. Windows seven in running fine; however now when I try to start up xp I get the message; windows root system32 hal dll, file is missing or corrupted. I have found imformation on the internet about how to fix this, but none of the example involved a dual boot drive. will this be affected? Will I need to re-install both os's? If anyone know anything about this that would be really helpful Thanks.