Seriennummer wird bereits von max. zulässigen Geräten genutzt.

Which software and version are you trying to install on your laptop?

I ask because Creative Suite 1, 2 and 3 cannot be activated. The activation servers were taken offline years ago.  Those products are officially dead.

When you can't deactivate a serial number
BE SURE TO ONLY ASK FOR ACTIVATION SUPPORT TO ADJUST YOUR ACTIVATION COUNT
You may need to PERSIST or TRY AGAIN to find a support agent with more experience
Click here https://helpx.adobe.com/contact/support.html

-click the chat icon at the bottom right of the page to open a chat session
-the chat icon looks like '3 dots inside a circle' at the lower right
-type AGENT into the chat window to connect directly to a person rather than the AI
Do be aware that Adobe's staffing is impacted by the virus, so wait times are long
.
Also: beware of answering anyone who sends you a private message
-click for more information about scammers https://tinyurl.com/10791730