Installation of SP2 error "System cannot copy the file atapi.sys"

Everytime I try to install SP2 I get the subject error.  I have done a Search and verified that the file is in Windows\system32\drivers where the installation program is looking, I have copied an new copy of atapi.sys to this folder and tried to point to another location where atapi.sys exists, all to no avail.  I have made sure Roxio Drag-to-Disk is not running - any ideas?