I did a PCB last week and all printed fine, no problems with printers.
Today I've tried to print a new PCB and have the 'no printers found' window.
After some head scratching I remembered what has changed.
I removed Norton antivirus and installed Comodo internet security,
Looking at the logs, in the Comodo Defence+ section, all windows access requests from PCB.exe have been blocked, but right clicking on all the blocked actions to set the file as safe and should be allowed give a response that Comode thinks the program is deemed safe already but it still blocks all window requests.
I disabled Comodo Defence+ and my printers came back into PCB edit.
At the moment i do not know how to tell Comodo not to block any windows calls from PCB.exe
Hope this is a help to others and that maybe others can find a way to tell Comodo not to block the calls.