Project locked into silence (more than one project affected)

Graeme McTaggart
I had to delete my first attempt at a song and start again from scratch
 
 
At any point in time, my project can go silent, voiding all my work.
 

Graeme McTaggart
I deleted the project because, once Sonar starts displaying the "master assigned to silent hardware" message, there is no way that I can work out, of restoring that project to the state of being audible.
Every time this happens, if I start a new project during the same session, it will be fine, but the file with the problem stays locked.
The same message will be displayed if I open the project; so, even though Sonar is configured correctly at that moment, it will not reroute that project to the selected, functioning audio device.
It makes no difference whether I'm using speakers or headphones, once I get that message, it's the kiss of death for that project.
 
I am working my way through the 2188 page pdf, learning as I got.
Sonar is basically similar to FL, it is the more crowded interface which is taking time to get used to.
Yesterday's track had a single instance of Strum Session with 12 bars in the piano roll. Nothing else.
I was just starting to programme the track and I'm still getting used to the piano roll in Sonar. (I find it tricky to work with at present).
 
I work abroad, so I never considered buying an audio interface, mainly because I never record anything, and also because it would be additional weight in my luggage and FL works fine on my notebook without one.
I don't know how heavy these things are or their dimensions, but I would either have to abandon it next summer or else pay to have it couriered to my home address.
If the only solution to this problem is to buy one, then in all honesty, I would have to seriously consider paying another £200/$300 to update FL Studio and see how many instruments from Sonar will work with FL.
 
I have gone through the audio hardware setup mentioned above and everything listed on the page matches my actual settings.
Share Audio Devices is not ticked.
The default device is the onboard speakers at present.
Once the headphones are plugged in, they are listed as an additional option.
I agree, I will have to Save AS every session, so that I can go back to the other version if/when I hit this problem.
I hadn't done that because I haven't got anything significant done in Sonar so far.
I'll start a third attempt at creating a basic project this afternoon, but I'll check back here first.

Graeme McTaggart
Whilst I thank all the contributors for their input, it really does look as though I've made an expensive mistake.
I tried the Sonar demo, which is next to useless in my opinion, having only the TTS1 and no save option, but was seduced by the prospect of a good range of instruments which suited my needs in the Platinum version, unlike Cubase 8 or FL 12.
I wanted a change from FL Studio after six years of compromises.
My problem with FL Studio is that I regard the instruments as inadequate for my purpose and of poor quality (except Sytrus).
 
Having considered all of your advice, it looks as though I will always have the problem of the silent lockout with Sonar on this notebook, so I'm going back to being productive on FL.
At least my old version of FL runs like a beast on my new notebook.
I'll try setting up Sonar's instruments and see what happens.
 
Please consider this post closed, thank you.

Graeme McTaggart
I'm not going to respond to the "takes more than 5 minutes" comment above.
That doesn't help or even contribute to the discussion.

Graeme McTaggart
The whole situation reminds of when a certain software manufacturer would release a new version of a familiar programme, but with new names for familiar things and a new menu structure, just to confuse the users and drive them towards paying for a training course.