Nothing is installed on Ubuntu 17.04, apt-get doesn't work

Hello everyone, I recently took a friend's computer, because mine broke, there is Ubuntu here and of course I can't rearrange it. The problem is that I can't put ANYTHING here!!! I searched Google for a very long time looking for a solution, but I didn't find anything, so. To begin with, I naturally tried using apt-get install (I did update repeatedly, the situation does not change) when I try to install any program, I get this

"E: Unable to correct problems, you have held broken packages."

Googled it, advised autoremove, dpkg --get-selections, aptitude (which I can't set), in general, I did all this, tried to change the repositories, but it didn't work, the window pops up

"Failed to download repository information"

The solution to this, of course, I also Googled, but nothing helped, when I try to install updates, it also comes out.

I also tried to install deb packages via dpkg-i, another error pops up:

Errors were encountered while processing:
 virtualbox-5.2:i386

VirtualBox for example, although that's what I need to install.

In rummaged through a lot of things, but either I didn't find anything (apparently it's about me)))

I ask for help because this is a VirtualBox I need and I can not use anything else (DZ for the university must be done)

I am waiting for your comments and answers, I will provide everything that you ask for)