Problème Photoshop sous windows 7

You should be able to use your photoshop subscription on windows 7 if you have latest updates for windows 7 and by following this procedure for enabling Transport Layer Security (TLS) 1.2 protocol.

https://helpx.adobe.com/x-productkb/multi/eol-tls-support.html

https://helpx.adobe.com/fr/x-productkb/multi/eol-tls-support.html

Photoshop 2020 (ps ver 21.xxx) is the newest photoshop version that runs on windows 7.

https://helpx.adobe.com/photoshop/system-requirements/2020.html

Current versions of Photoshop require Windows 10 or later.

https://helpx.adobe.com/photoshop/system-requirements.html

You will need to contact Adobe support for a download to a previous version compatible with Windows 7.

https://helpx.adobe.com/contact.html - log in to the site with your user ID and click the chat bubble in the bottom right.

Then go to your Creative Cloud Desktop application and disable automatic updates.

https://helpx.adobe.com/creative-cloud/help/creative-cloud-updates.html

Is this a TWAIN driver? Modern versions of PS do not support TWAIN. 

As for: " I can no longer use my online version of Photoshop" you are subscribing to an Adobe plan that includes Photoshop, what version are you running or trying to run?