Trying to get any software to install from Gnome Software file results in a message indicating that the installation could not be completed. Same deal on a software for Linux that was downloaded for installation (4K Video Downloader). I just used the terminal to install Inkscape and that worked. Any ideas?

One other little thing, the launcher now contains an icon that is a gray box with a question mark in it. On mouseover, it indicates "Waiting to Install". I can click on it, but noting happens.And, this is an Acer Chromebook R11 CB5-132T-C1LK with Xenial Ubuntu installed via Crouton which other than the aforementioned is working just hunkey-dorey.

Open a terminal and issue

I did it and tried to install Screenshot, and still got the same message, "Sorry, this did not work Installation of Screenshot failed". What was that supposed to do?

That should prompt to correct any missing packages needed by another package.
You have to run it with affirmative options and allow it to fix what it finds broken,

Got the whole line I should run, you lost me on that one. I'm not that terminal savvy.

Can you please run the following command:

That will show which packages, if any, are improperly installed.

Could you also let us know which distro (and version) you are running.

Your sidebar says Mint 18.1 Cinnamon, which clashes with the idea you are trying to run GNOME Software.

The sidebar refers to the large laptop. This one with the GNOME Software issue is an Acer Chromebook R11 CB5-132T-C1LK with Xenial Ubuntu installed via Crouton (sudo sh ~/Downloads/crouton -r xenial -t unity,touch). I have also run update and upgrade on it. One of those two fixed the lack of software listed on it. Now it just give me that message the installation failed and not much else. Again, I seem to be able to install software vial the command line, assuming I have the correct name for the package - which isn't always what it is called, hence the need to have the GNOME Software app running. I hope that helps.

Do you get any error messages on the command line when launching GNOME Software from there and trying to install a package?

Nope, command line installs worked perfectly. The only other way to get that error is to download a Linux software package (in this case 4K video downloader) and attempt to install it from the Download directory (which worked fine on the larger Linux Mint laptop).

No. What I mean is, can you please run Gnome Software from the command line (gnome-software), go through a failed install process in the GNOME Software window that opens, then close GNOME Software and paste here all the output that there has been in the terminal window since you issued the gnome-software command. That output may include errors and warning messages that might shed some light on the issue.

The 4K video downloader problem we'll have a look at afterwards (we'll try to install it with gdebi, not the default GNOME Software).

It looks like Screenshot failed to load, and there were three or more pages of errors. I can't seem to be able to copy that and paste it in here. I copy it by selecting a page of it and use shift-ctrl-C to copy it, but when I try to paste it in here, nothing happens Ctrl-shift V doesn't work and either does ctrl V (or right click of the mouse for that matter). I though Libra Office was installed, but it isn't working. I tried to install gedit, but that doesn't appear on the software list and an attempt to run it from the command line doesn't get anywhere either. Maybe it's the distro I am using. Maybe I should just tap the space bar on startup and install Trusty instead. That one worked on the old Chromebook.

Copy, paste, and cut from gnome-terminal uses the shift-CTRL key combo. But most everything else just uses the CTRL key. So, for pasting in a browser, omit the shift key in the combo, and just CTRL-v.

Yea, I tried that. First the Adblocker on FireFox blocked the paste with some weird box (yup, that's real technical), and after I removed that from FireFox, the CTRL C just did nothing.

There is an olde addage, If it ain't broke, don't fix it. Well, Trusty is LTS for a few years and the other cheaper Chromebook is up and running on that with no real problems (gets an error pop-up once each session, but I can live with that). All applications run, and that's what I have these things for in the first place, not working on the OS. So, I think it's just time to tap the space bar on power up tomorrow and reinstall the Ubuntu thing with Trusty. This Xenial thing as been nothing but a headache from the start. Yea, Ubuntu kinda sucks compared to Linux Mint, but until Crouton is able to install Linux Mint with the Cinnamon desktop and there is some run time on that to get the bugs out, I will just stick with Trusty as it does work. Most of what I do is done on this larger laptop, running Linux Mint 18.1 with the Cinnamon desktop. I just couldn't resist making the Chromebook do a lot more than they are supposed to do, especially offline! Don't think for one second that I don't appreciate all the effort everyone has put into trying to make this Ubuntu Xenial distro disaster work on the Chromebook, because I really do, and would never have even bought it if it weren't for the support I get here. You guys are the best!