Based on your description, it seems that the issue might be related to permissions and authentication. Although you have set the shared folders to be accessible for Everyone, there might be some additional security settings that are preventing access from other computers on the network.
Here are some steps you can try to troubleshoot the issue:
1. Check the network profile on all computers and ensure that they are set to Private network. You can check this by going to Settings > Network & Internet > Status and click on Properties for your active network connection.
2. Make sure that all computers are on the same Workgroup, in this case, WORKGROUP. You can check this by going to Settings > System > About and click on System info.
3. Verify that the computers can ping each other by opening the Command Prompt and typing "ping <computer name>". If there is no reply or if it times out, there might be a network issue.
4. Try accessing the shared folders using the IP address instead of the computer name. For example, instead of typing "\\CTDESKI7", try typing "\\192.168.0.X" (replace X with the actual IP address of the computer you want to access).
5. Check the permissions on the shared folders to ensure that they are set correctly. Right-click on the folder, select Properties, and click on the Sharing tab. Click on Advanced Sharing, then click on Permissions. Verify that Everyone has full control.
6. If you are still having issues, try creating a new user account on each computer with a password and set the same username and password on all three computers. Then try accessing the shared folders using the new account credentials.
7. Finally, if you have any third-party antivirus or security software installed, try temporarily disabling them to see if they are blocking access to the shared folders.
Hopefully, one of these steps will resolve the issue and allow you to access the shared folders on all three computers.