Instrument and accents gone

There's nothing non-free version.

1. There is only the free version. There is no paid for version, and no way to pay for one if there was.
2. Breath marks, slurs, repeats etc are found in the pallets which by default are shown in a panel on the left of the screen. Make sure that "Pallets" is ticked in the View Menu.
3. Rests are available in the note entry tool bar. Make sure that "Note Entry" is ticked in the [View]>[Toolbars] Menu.
4. If you create a new score [File]>[New], after adding the title etc. and clicking [Next], you should see a dialogue that gives you the option to use a ready made template. Under the General section you should see an option "Choose Instruments". When you click on that the Instrument selection dialogue opens. By default only "common instruments" are shown but if you click on that "Common" tab you should see a drop down that includes other categories - e.g. Pop/Rock, Jazz, Orchestra etc and at the very top "All". Clicking on one of those options will show a list of instruments relevant to that category. Clicking on "All" will show a very long list of all the instruments MuseScore knows about.

For more information see here https://musescore.org/en/handbook/3/create-new-score and here https://musescore.org/en/handbook/3/note-input and here https://musescore.org/en/handbook/3/palettes
In fact, read through the whole of the Basics section of the handbook. The time spent will be well worth it.

You wrote:
When I first loaded the musescore...

You loaded MuseScore onto what? Onto your Galaxy? Onto a laptop or desktop computer?
What version of MuseScore?

I even had a synthesizer....

Do you mean a MIDI keyboard used with MuseScore? Where did it go?

Now a fer instruments and cannot use accents to my music.

I don't understand the first part, but...
...please attach a score, explaining exactly where you want to add an accent, how you go about entering it, what you expect to happen, and what happens instead.
See:
https://musescore.org/en/node/289899

To summarize:

1) there is only a free version, there has never been any non-free version
2) all versions of MuseScore contains accents, breath marks, rests, slurs, etc - no version of MuseScore has ever lacked those basic features

So, if you are having trouble finding those things, we'd need more information in order to be able to understand and assist better.

For instance, rests on normally entered via the keyboard shortcut 0 or by right-clicking, but there is also a toolbar icon for them, right in between the tie icon and the accidentals. Are you saying you don't see it there? Can you post a screenshot if it?

Accents, slurs and repeats are found on the palettes on the left of the main window, right where they have always been. Accents are int eh Articulations palette, slurs in the Lines palette, repeats in the Barlines palette, right where they have always been. Breath marks are in the Breaths & Pauses palette, but if you're just updating from a years-old version, you might be starting out in the Basic instead of Advanced workspace and that palette wouldn't show by default. So simply switch to it using the control at the right right of the toolbar.