Aktivierung CS3 [Dead product]

Impossible.  CS3 is 16 year old end of life software.  Even if you could activate it (you can't), it's unlikely it will run properly on modern equipment. 

You need new software.

MODERN OPTIONS:
Photoshop Elements (no subscription needed).
https://www.adobe.com/products/photoshop-elements.html

Creative Cloud Photography Plan (approx $10/month for 12 months). Includes the following:

• Photoshop CC and Photoshop on iPad
• Camera Raw
• Lightroom on desktop, mobile and the web
• Lightroom Classic
• Portfolio website + hosting
• Adobe Express (free starter plan)
• Bridge
• 20 GB cloud storage (upgradable to 1 TB).
• Free upgrades for paid subscribers

https://www.adobe.com/creativecloud/photography.html

Premium Adobe Express ($10/month).

• Creative Cloud Express app (web and mobile)
• Premiere Rush (video editor desktop and mobile)
• Photoshop Express (mobile)
• Spark Video (mobile)
• Spark Page (mobile)
• Adobe Portfolio + hosting
• 100 GB of cloud storage
• All premium templates and design assets including the collection of over 160 million royalty-free Adobe Stock photo collection.

https://helpx.adobe.com/express/using/express-overview.html

Creative Cloud All Apps (51 + apps & services) and Single App Plans
https://www.adobe.com/creativecloud/plans.html

you can not.

the block is on adobe's end so there's nothing you can do to bypass, or work around it. ie, the activation servers no longer function so it's not possible to activate and use beyond the 30day trial period on any one computer.

Hallo Community,

diese Woche wollte ich aufgrund einer Neuinstallation meine damals legal erworbene CS3 neu aktivieren, was aufgrund der abgeschalteten Aktivierungsserver nicht mehr geht.

Mir tut es die CS3 nach wie vor wunderbar, und es wäre schön wenn mir jemand einen Tipp hätte, wie ich die Version doch noch aktivieren kann.....es ist schließlich ein Produkt, welches ich mal teuer bezahlt habe

Merci und viele Grüße