Right, Your fast and easy advice resolved my problem. But here is one more, maybe small question: installation of NoMachine gave me this info:
The NoMachine setup procedure could not detect your PulseAudio
installation: either PulseAudio is not installed on your system
or it was installed in a non-standard path. If PulseAudio is not
available, NoMachine audio support will try to rely on ALSA device.
Please note that you can enable PulseAudio support at any time;
to do this make sure that you have PulseAudio installed, then run: