acpi.sys is corrupted on boot? any ideas?

I was getting ready to format a computer that I receieved a while back and I received the error "acpi.sys is corrupted press any key to continue" during boot. So I tried putting the windows XP disc in to format it and that wouldnt work. So I installed the drive as a slave and formatted it, that worked. Now I have a formatted drive that I still cant install windows xp on due to this error. Any ideas on how to get rid of it? Im all out. Thanks

The computer is a...

Compaq 5400
1.3ghz
384 ram
15gb hard drive

 

I reailzed at work today i meant to say the windows xp cd works fine, i reinstalled it on another computer just minutes prior to trying it on this one. I will swap out the memory from one computer to another and see if that helps. Thanks, any one else have any ideas? Bad cd drive?