I can't find in new release of Navigatrix the software for remote desktop, can you help me?

I think the application you are looking for is called gitso.

For some reason the menu entry (Menu> Internet> Remote Support) is not working on this machine. It might be my own doing as I tend to break things.

If the menu entry doesn't work for you, it will work if you can call the application from the terminal Good luck.

No way Moe, i'm sorry but I mean the software I'm looking for is the similar of Remote Desktop on Microsoft Windows, and in the older version of Navigatrix there was it, I remember that it worked properly, but now there is only Gitso, but this is a software used to request assistance like "Teamviewer"

Here it is:
https://apps.ubuntu.com/cat/applications/vinagre/
but I don't know how install it.

That would be Menu> Preferences> Package Manger.

If this is your first time, Reload. The "Quick Find' will show up after a first time reload-restart. If you're going to do a lot of software investigation (Why not?), pick a repository closer to your currently location via the Setting> Repository menu. It's not necessary, but can help with speed, depending on how much you do.

Poke around. Click a wrong button. At this level of interaction, it's hard to do damage more painful than the loss of time/money installing/re-installing. The education is always more valuable.

When you have a updated list of available package, search for vinagre, tick the box to add/remove package(s), go wild.

From the command line that would begoing wild is not essential.

Thank you Moe, you are always a gentlemen!