Adobe web premium cS4 activation issue

Is this an individual license or a volume license?

For help with volume licenses, visit the Adobe Licensing Website | Serial numbers, orders, and accounts​.

For an individual license:

1. Are you getting the error message when you attempt to install CS4? If yes, are you installing from disc or download? For downloads, make sure you are installing the exact version of the CS4 you originally purchased.
   
   
2. If you are installing the correct version and you still get an error, try the solutions in this help document: Error: "The serial number is not valid for this product" | Adobe Creative Suite​.
   
   
3. If those steps fail, Contact Customer Care via chat to confirm you're using a valid serial number. Chat technicians are unable to provide technical support for older software like CS4, but they can answer questions about your license.
   
   
4. If chat support confirms your serial number is valid and you are still experiencing issues, you can try running the Microsoft Program Compatibility Troubleshooter: https://support.microsoft.com/en-us/help/15078/windows-make-older-programs-compatible​. No guarantee, but it has helped some folks.

Let us know whether that helps or you need further assistance.