Cant play 'cracked' games

[mmansons]

Hey dudes!

I was wondering if someone could help me find why I cant play 'cracked games'. I installed rise of nations and Age of Empires 3 (which I own) and they worked just fine, but when I replace the .exe files so I can play without the CD, the game takes me back to desktop with an error message:
AppName: age3.exe
AppVer: 4.105.1007.3243
ModName: unknown
ModVer: 0.0.0.0
Offset: 00000000

Recently I had to reformat my hard drive and thats when the problems started. I used to be able to play 'cracked' games just fine. I also recently installed Norton System Works 2006

I am running on a Gateway Desktop with Windows XP Media Center Edition 2005.
10024 MB of ram
Pentium D processor

Any help will be much appreciated!