there are music files on the cd-rom
and registry entries wich are pointing to the dir of the files.
patch the registry value like 'Music -cdrom dir' to
'Music .\\' and copy all music tracks in your NFS dir on your harddisk.
and krondike remember, there arenīt only the '74' and '75'
to play with when cracking cd-checks
but i think nfs is very easy.
like tippex said, search the error message in the references,
scroll some lines above and check for a call / jump wich executes
the check and pops up the msgbox.
i will search my old nfs copy to check this funny thing out.