Complete music library on iTunes disappeared

Hi there and thak you for your responses.

Sorry but I am rubbish when it comes to computers.

I tried the backup and restore but once again what I am seeing on my PC doesn't seem to fit the norm.

If I go into my file explorer and click on the NAS it shows the iTunes library but still with the 7z suffix and is dated 4th January (see picture)

So, I assumed that would be the one I am going to use when prompted to 'choose lobrary'. Within these iTunes files on the NAS there is no pevious libraries.

However, when I get the message 'choose library' pop up and click on it, as normal it takes me to my file explorer once again but when I click on the iTunes folder in my NAS this time whilst there is an iTunes it shows no libraries (see picture) and no matter which yellow file I click on no 'Libraries' are shown.

Yet if I click on the 'Music' file all my music is still there as individual files as in the picture below.

So, what I can't understand is why the Library files are there when not going through the iTunes 'choose library' and not there when I do.

I tried copying the Library file from the iTunes file on my NAS onto my desktop but the file is to massive for my computer (over 2TB) which is why it is not kept on my PC in the first place and I got a NAS.

I don't understand why the pathway which was working perfectly well before is no longer picked up by iTunes. Nothing has changed as far as I can see.

Sorry but I am totally flumoxed as to what to do. This has worked well for years and now seems to just decide nope don't like it. As I said it took me months and months and several CD burners to burn all my 2000 plus CD's onto iTunes before all my CD'S were stored away in the loft. Apart from that, this also means I can't burn any new CD's on to iTunes on my NAS I may get, such as the ones I had for Christmas

I have a CD ReWriter connected externally to my PC as like many, my current PC does not have a CD player/burner.

As you can see the front face of iTunes is on my PC which I just click on to open...

And this is what I currently see...

Before it showed all my burned music. When I put a CD in the burner to transfer into iTunes it reads the CD then this appears...

I then check to make sure I don't want to change anything in the description etc...

and then click on the import button and it transfers onto iTunes...

When completed, I go into iTunes and there it is complete, with album cover.

I then go into where the music and iTunes is kept on my NAS (File Station & QMusic 5) to check it is there, which it always is.

I do not add any extensions everything is done automatically. If I want to play any music via iTunes, I have just to open it and because the path to the music kept on the NAS is there in the advanced preferences, it has always seen it and showed it and played it.

This is how it has worked since day one of burning all my music onto iTunes about five years ago and nothing has changed. I do not know what gives the iTunes library the 7z suffix when stored in the NAS and to be honest I've never took any notice of that before. I have not and am not aware of zipping the music files the computer does what it does when I transfer the music onto iTunes.

As I have said because of the size of my music file I cannot keep it on my PC which is why it is kept on the NAS. Only since clicking into iTunes last week has the empty iTunes appeared (appart from the U2 freebie) even though the path to where the music is kept on the NAS (which can be seen in the 'File Station' screen shot above) is present and has not been changed. This has worked well for years and now it's as if it never existed.

Sorry if I seem to be repeating myself and put loads of screen captures on but as I said I am not very good with computers and it is the only was I can explain it.