How to Fix an Invalid CD Key
- 1). Delete the CD key that you have entered. Check your keyboard and ensure that the "Caps Lock" button is not engaged by finding the "Caps Lock" light. Turn off Caps Lock by tapping the button if it is illuminated. Re-enter your CD key exactly as the software shows it. (Do not type dashes and other character separators unless instructed to do so, as most programs include this syntax automatically.)
- 2). Type "O" instead of "0" or "I" instead of "1," as some fonts and printed materials make it difficult to discern one from the other.
- 3). Check the software developer's support pages for known problems with CD keys. You may have to drop characters from keys, type the key in backward or download a patch or update for your software.
- 4). Contact the software developer's technical support section. Find the developer's name on the installation disc or on other software packaging, such as the manual or quick install guide. Report your problems with your CD key, and request a new one. Some developers may charge you for a new key or require that you submit a receipt to prove ownership. Prepare to pay for a new key if you purchased your software used or if you cannot prove ownership.
Source...