PDSD LYDY 057D
ELQU E4DQ SSJE JPGL 46B6
DJUD QJJD 4P44 GDJP 57B0
PLT4 DYD8 4LLD J4Y2 3758
SWYT GMEY ETEM SSQW 1A8C
Modify yourself:
Open the run input registry
Look for the following path
HKEY _ LOCAL _ MACHINE \ SOFTWARE \ Activision \ Call of Duty 4
The codkey parameter in the second line is your current cd-key. Just cover the original number with a digital tube. Note that no separator is needed in the middle.