I think this is what you are looking for.
http://twistermotorsports.com/utilitie.htmAt the bottom of the page.N2003 No CD PatchThis patch will allow you to play N2003 with out the cd. But you will not be able to use it to log on Sierra. Rename nr2003.exe to nr2003.exeoriginal or something other than .exe. It will warn you that the file might not work so say OK. Change the name of no cd patch to nr2003.exe.N2003 No CD Patch v1.2.0.1Same as above but use this patch with the 1.2.0.1 patch.N2003 1.2.0.1 Patch