Just installed 6.07.3. Windows 7. Can print from other programs, but LO leaves print queue empty. Reinstalled the printer, but the problem persists.
Verify you have a predetermined printer selected.
On the system panel control go to Uninstall programs, and select LibreOffice to uninstall.
But I think you can try to install a newer version Download LibreOffice, or restart with a clean profile Menu/Help/Restart in Safe mode.