I've installed Mac OS X 10.5.7 original DVD from Apple and under my About This Mac. It is showing my Model as "MAC" and Model Identifier as "System Product Name". Somebody told me because of this, might cause some problems with my some programs. Is there a way to solve this problem???

Thanks for the help

That´s not going to give you any problems mine says i have a mac pro something something but all programs work. If your proccesor shows up correctly and your videocard is working most programs should work fine.