I can neither open nor uninstall Steam (Ubuntu 16.04 LTS) [duplicate]

My Steam have apparently become completely unfunctional: If I try to open it, the icon flashes for a few seconds and nothing happens afterwards. If I try to uninstall it (Ubuntu Icon >> Search for 'Steam' >> Right button >> Uninstall), there are also no results.

I'm very new to Ubuntu and I've recently upgraded it to the last version expecting it was the right thing to do, but I don't know if it was really. Do any of you guys know how to fix this?

Edit:

Thank you both for your replies.

I've tried typing 'steam' on the terminal. A bunch of messages then appeared and it upgraded Steam (I think) and opened it. I closed everything and restarted the computer. Now I can open Steam, but every time I do so a warning pops up saying:

    home/egavs/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-genu/libtinfo.so.5: no version information available (required by bash)
    Your steam package is out of date. Please get an updated version from your package provider or directly from http://repo.steampowered.com/steam for supported distributions.
    Press enter to continue

When I press Enter, the message closes. Steam is a bit slow and sometimes it not even connects to the network. Also, I still can't uninstall it in the way I first tried. Nothing shows up when I type lspci | grep VGA in the terminal. When I type 'steam' on the terminal now, Steam opens and the following appears (SPM is my computer's name):

egavs@SPM:/$ steam
Running Steam on ubuntu 16.04 64-bit
STEAM_RUNTIME is enabled automatically
/bin/bash: /home/egavs/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by /bin/bash)
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Gtk-Message: Failed to load module "gail"
Gtk-Message: Failed to load module "atk-bridge"
Gtk-Message: Failed to load module "unity-gtk-module"
Installing breakpad exception handler for appid(steam)/version(1465948400)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 80: saw unknown, expected number
[0706/231122:ERROR:main_delegate.cc(779)] Could not load cef_extensions.pak
[0706/231122:ERROR:browser_main_loop.cc(217)] Running without the SUID sandbox! See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_suid_sandbox_development.md for more information on developing with the sandbox on.
Installing breakpad exception handler for appid(steamwebhelper)/version(20160614232302)
Installing breakpad exception handler for appid(steamwebhelper)/version(1465946582)
[0706/231122:ERROR:main_delegate.cc(779)] Could not load cef_extensions.pak
Installing breakpad exception handler for appid(steamwebhelper)/version(20160614232302)
Installing breakpad exception handler for appid(steamwebhelper)/version(1465948400)
Installing breakpad exception handler for appid(steamwebhelper)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
Created shared memory when not owner SteamController_Shared_mem
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)

** (steam:4043): WARNING **: Unknown device type 14

** (steam:4043): WARNING **: Could not create object for /org/freedesktop/NetworkManager/Devices/1: unknown object type
Installing breakpad exception handler for appid(steam)/version(1465948400)

** (steam:4043): WARNING **: Ignoring invalid property 'secondaries'

** (steam:4043): WARNING **: Ignoring invalid property 'autoconnect-priority'

** (steam:4043): WARNING **: Ignoring invalid property 'route-data'

** (steam:4043): WARNING **: Ignoring invalid property 'address-data'

** (steam:4043): WARNING **: Ignoring invalid property 'route-data'

** (steam:4043): WARNING **: Ignoring invalid property 'address-data'
Generating new string page texture 2: 48x256, total string texture memory is 49,15 KB
Generating new string page texture 3: 384x256, total string texture memory is 442,37 KB
Installing breakpad exception handler for appid(steam)/version(1465948400)
Installing breakpad exception handler for appid(steam)/version(1465948400)
roaming config store loaded successfully - 619 bytes.
migrating temporary roaming config store
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 80: saw unknown, expected number
Installing breakpad exception handler for appid(steam)/version(1465948400)
Failed to init SteamVR because it isn't installed
ExecCommandLine: ""/home/egavs/.local/share/Steam/ubuntu12_32/steam" "
Installing breakpad exception handler for appid(steam)/version(1465948400)
System startup time: 4,04 seconds
bash: /home/egavs/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by bash)
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
Warning: Your steam package is out of date. Please get an updated version from your package provider or directly from http://repo.steampowered.com/steam for supported distributions.
Generating new string page texture 73: 256x256, total string texture memory is 704,51 KB
Generating new string page texture 74: 128x256, total string texture memory is 835,58 KB
Generating new string page texture 75: 128x256, total string texture memory is 131,07 KB
Generating new string page texture 76: 64x256, total string texture memory is 901,12 KB
Generating new string page texture 77: 32x256, total string texture memory is 933,89 KB
Running Steam on ubuntu 16.04 64-bit
STEAM_RUNTIME has been set by the user to: /home/egavs/.local/share/Steam/ubuntu12_32/steam-runtime
/bin/bash: /home/egavs/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by /bin/bash)
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
/usr/bin/ldd: line 119: printf: write error: Broken pipe
ExecCommandLine: "/home/egavs/.steam/root/ubuntu12_32/steam steam://open/driverhelperready"
ExecSteamURL: "steam://open/driverhelperready"

Should I download one of the suggested packages? They don't seem to be for version 16.04.