If you previously purchased CS3, you cannot use your original discs to reinstall the software because they require the defunct activation servers. Instead, Adobe provided a special version of CS3 that does not require activation.
: Adobe previously hosted a specific download page for CS3 users that provided a new installer and a replacement serial number that bypasses the activation server. Photoshop cs3 serial number and authorization code
: Adobe no longer supports phone-based activation for CS3. If you previously purchased CS3, you cannot use
Finding a serial number or authorization code for has changed significantly because Adobe has retired the activation servers for this legacy software . The Status of Photoshop CS3 Activation : Adobe no longer supports phone-based activation for CS3
: Go to the Adobe ID portal and sign in with the account used for the original purchase.
Note: Adobe has since removed many of these direct download links for older software. If the link is no longer available in your account, you may need to contact Adobe Support with proof of purchase to see if they can provide a download link. Understanding the Authorization Code
: CS3 is not compatible with modern operating systems (like macOS Catalina or newer, or 64-bit-only versions of Windows). It is best run on older hardware or virtual machines.