I'm reitring my old computer and trying to reinstall CS4 on my new one. I used BelArc Advisor to find my 24 digit software license number. I downloaded a trial version of CS4. When I enter the license number to register my program I get a red x. When I try to register it with Adobe they say the serial number is already in use. Yes it is in use I've used it for over 10 years. I'm 70 and reitred now and only have a one customer I routinely use it for so I don't want to go to the subscription service. Any ideas on how to register CS4 on my new computer?
You should have deactivated on the old machine first. If you still have access to it, then do that.
But...there's almost no chance that CS4 will run properly on Windows 10 and it certainly won't work on a new Mac.
I've used it ever since I went to Windows 10 on my old computer without any issues. It won't let me deactivate it on my old computer.
You can pay a bit more for a subscription to InDesign CC and use it, and pay for it, only by the month(s) you need it for.