I'll try to help.
What account are you logging on to each desktop with? You mention PIN, are you using the same Microsoft account on each desktop? Or are you logging in with a true local account? Did you try to map a drive between machines with a different account? Local accounts would need to have the same password on each machine.
Launch Computer Management and open Local Users and Groups. Select the account in question and uncheck "Account is locked out". You might also want to check "Password never expires" so that you don't run into that in the future.
If you are running the Home version of Windows, use a command prompt with "run as administrator" to unlock the account.
net.exe user WhateverUserNameYouUse /active:yes
Did you save credentials for any of these machines? You may have typed in the wrong password.