I can no longer open any files in Photoshop

We can't help without any further informations about the error and your system.

What doesn't work? What do you do or try to do before the error occur?

Which steps do you have tried to solve the issue?

Do you get any error message(s)? If yes post the message(s) word-by-word (or post an screenshot of the message).

We need also informations about your system. The best is to provide a copy of your 'System Info' if it's possible. This can be get from the Photoshop menu item Help > System Info. There's a copy button in the System Info dialog. Press this button and paste the info into your next forum post.

Try to manually removing the preferences files. This is the most complete method for restoring to the default state. The manual method ensures all preferences which may be causing a problem and prevents Photoshop form loading.

Please follow the steps below:

1. Quit Photoshop.
2. Navigate to Photoshop's Preferences folder.
   MacOS: …Users/[user name]/Library/Preferences/Adobe Photoshop [version] Settings
   Windows: …Users/[user name]/AppData/Roaming/Adobe/Adobe Photoshop [version]/Adobe Photoshop [version] Settings
    
   Note: The User Library folder is hidden by default. To access the content in the hidden folders see here:
   MacOS: Access hidden macOS library files
   Windows: Show hidden files, folders, and filename extensions in Windows
    
3. Drag the entire Adobe Photoshop [Version] Settings folder to a safe place to a backup your settings
4. Open Photoshop.

 New preferences files with the default settings will be created automatically.