My CD-KEY or unique identification doesn't work

Updated: 12/29/2017 by Computer Hope

Tip: This document is for users having trouble entering their CD-KEY or unique identification and not for users who have lost their unique identification number.

The unique identification number or CD-KEY that comes included with the software or your computer should always work. However, there are different reasons that can cause the number not to work, as mentioned below.

Entering the wrong code

If you are installing Windows and the code you are entering is not working, make sure it is the correct code. With many OEM computers, such as Dell, Hewlett Packard, Toshiba, Sony, etc. the manufacturer will place the code used with your computer on the back or bottom of the computer. Use this code to install Windows on your computer. However, keep in mind that if your computer came shipped with Windows XP and you are trying to install Windows Vista, the code on your computer only works for Windows XP. You would need to use the Windows Vista code that came with the software package.

Microsoft Windows XP Product Key

Below are some additional reasons a Microsoft Windows product key may not work.

  • Each version of Windows has its own unique product key. Meaning a Windows XP Home product key is not going to work for Windows XP Professional.
  • An upgrade Windows product key is not going to work for a full version of Windows.
  • A Microsoft Windows OEM product key will not work with retail versions of Windows.

Using the wrong character

Make sure all the letters and numbers you are entering are correct. Characters such as "O" and "0" can be difficult to read, make sure it is a "O" and not a Zero that needs to be entered. Other problem letters include a capital "i" that looks like an "l", or an "l" that looks like a "1".

If you have tried all combination of letters and numbers, enter the code as someone else reads it out loud.

Maximum installed copies

As a form of protection many programs, especially games, only allow a few copies of the program to be installed. If you have shared the unique identification number with friends or installed the program onto multiple computers, you may have reached the maximum allowed copies that can be installed.

Tip: Never share your unique number or software with your friends or family.

Code disabled

Program is a pirated copy and using an invalid code or a disabled code. Downloading a program from the Internet or buying a program from an auction site such as eBay are two common ways a scammer may distribute pirated software. If you have tried the above suggestions and are still unable to get the program to accept the CD-KEY, the number has been disabled or was never a real number.

Finally, you can contact the developer of the program to see if a new product key or CD-KEY can be given over the phone. However, if they decide you've purchased a pirated copy or have exceeded the maximum allowed installations they will not give you a new number.

Additional information