isapnp.sys corrupted or missing access is denied

[CyberThug]

Fellas,

environment:
server 2003 enterprise
ntfs

background:
had a harddrive in the raid go bad
rebuild the harddrive
reboot and got the following error

isapnp.sys is missing or corrupted - run system recovery from CD to replace the corrupted file, which i did using

http://support.microsoft.com/kb/315311

however here's my problem: I am getting an "access is denied"

here's what i've tried:
1. attrib -r -s -a -h the file
2. reseating the ram modules

Thanks in advance for your help.

If the world end today, don't say I didn't warned you.