windows XP upgrade help

I just installed a fresh copy of windows XP professional and I went to do the windows update

I'm trying to install the SP1 but when it starts it gives me the error "The file d:\windows\system32\drivers\atapi.sys is open or in use by another program, please close all programs and retry"

I have everything I can think of closed down and don't see that file being used in the task manager

anyone know what it is and how I can fix it

Restart?

Restart in safe mode?

i think atapi has to do with cd rom drives.

but yeah, reboot and try it in safe mode.