Can't install 7zip on Ubuntu 15.10

[albertoamoruso]

Hi! I'm a new Ubuntu user but I find myself unable to install 7zip on my computer.

I first tried through the Ubuntu Software Center but it didn't work and a warning appeared stating:

Failed to download repository information - Check your Internet connection.
I don't know what repository are but I know my connection works perfectly indeed.

What can I do?

I tried to install a couple of different softwares, only obtaining the same result.

Thanks in advance! :D

[Topsiho]

Hi,

Ubuntu 15.10 is obsolete, and you can't use it now. It was released in October 2015 and only supported for 9 months.
Best thing to do is get Ubuntu 16.04 (LTS: Long Time Support), which will be supported for 5 years, or wait until Ubuntu 18.04 will be released, end of this month. That is an LTS too, supported for 5 years.

a repository is sort of a warehouse for software that you can use with your computer. For Ubuntu 15.10 it doesn't exist anymore, reason you can't use it ...

Topsiho

[PaulW2U]

What can I do?
All I would want to add to Topsiho's excellent reply is that you could now install Ubuntu 17.10.1 (https://www.ubuntu.com/download/desktop) which is supported until late July 2018. You could then upgrade to Ubuntu 18.04 at your leisure before Ubuntu 17.10 itself becomes "End of life" and then not have to worry about further upgrades until 2023. Your choice. You might want to ask further questions about Ubuntu release support dates.

But whatever you do please do not continue to use Ubuntu 15.10. None of your applications will be updated or fixed with security updates. Popular applications such as Firefox, Thunderbird or Chromium are further applications that will never be updated for Ubuntu 15.10.

See https://wiki.ubuntu.com/Releases for a list of the currently supported Ubuntu releases and their "End of life" dates.