That "No command" screen is the default recovery menu that comes with factory images. Did you try flashing something before it happened? It's going to recovery I think because it can't boot /system/ for some reason. My advice would be to flash a new custom recovery again, then flash PA or whatever other ROM you want and see if that helps. Check the sticky
for steps to do all that flashing and download links for the recovery. Check the PA thread
for links to download and flash PA again.