Hi Svend
I am Dave, I will help you with this.
Adobe indicate that CS3 is no longer supported and they closed down the activation servers for that software a couple of years ago, how long has it been since you activated CS3 on your old Windows 10?
After you installed CS3 into Windows 11, were you able to successfully activate that software?
Create a desktop shortcut for CS3, then right click that shortcut and select Properties.
Click the Advanced button and set CS3 to run in Administrator Mode, then click the Compatibility tab and set CS3 to run in Windows 8 Compatibility
Save those settings and check if CS3 will run correctly.
If not, it would be best to post to the Adobe forum, to see if anyone has a workaround to get CS3 running on Windows 11
https://community.adobe.com/
________________________________________________________
Standard Disclaimer: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.