Medal of Honor: Allied Assault back up problem

[JaPule]

I am having problem backing up my copy of MOHAA. I made a copy using the latest version of clonecd and it say copy is complete. I thought everything was perfect then I reinstall MOHAA, it install perfectly. When i load up the game it say replace the CD. I guess there's a way that they know the copy is not the original CD. Any help please post here. I have to use the no CD crack to get it go work.

Sys. Spec:

AthlonXP 1900+ @ 2000+
MSI KT266
SB Live!
GF3 TI200 @ 200, 460
256 DDR PC2400