In most of the games the main executable is protected with SafeDisc, SecurROM or StarForce. The general idea is to replace this main executable by a modified (decrypted/unwrapped) executable where the CD/DVD protection has been stripped from (unwrapped).
Here are the instructions to be able to play a SafeDisc v2 protected CD using the unSafeDisc v2.xx.xx utility:
Install the game - Full Installation
Use the unSafeDisc Dumper to dump the SafeDisc protected executable (or DLL) to a <Game>.DATA.BIN file.
Use the unSafeDisc Rebuilder to create a modified executable from the <GAME>.DATA.BIN file.
Quit UnSafeDisc and rename the create TESTME.EXE to: <Game>.EXE
Copy the fixed <Game>.EXE file to the game directory - overwriting the existing one!
Play the Game!
In some cases it is also possible to make a working backup of a SafeDisc v2 protected game using unSafeDisc (in most cases the original or backup CD is required to be in the CDROM to be able to play it):
Create the following temporary directories:
Copy the full contents of the original CD to TempDir.
Follow the above included unSafeDisc instructions to get a working Fixed Executable.
Replace main executable: <TempDir>\<Game>.EXE with the Fixed Executable.
Burn the contents of TempDir to a CD-R using the same CD-Label as the original CD.