OK, put the back up of MOHAA in your cdrom and click my computer.
then right click the drive MOHAA is in and click on explore...this should bring up all the files on the MOHAA disc. there should be a read me file which is a white notepad looking icon with black lines to look like writing. open up the read me file and it should say what version game you have at the top, something like MOHAA version 1.0 or similar.
once you know the version just go the patch section on this site and download the appropriate version patch.
PS..it will probably be a winace file so you will need to download winace
WWW.WINACE.COM , install the program, then download the patch. do you know how to install the patch into the game folder? let me know if you dont or leave a msg here.