Command window keeps popping up and minimizes the game

[Ryuzaki]

So...whenever i open steam(just steam, no specific game), a black window (like the command prompt) keeps popping up every 20 seconds which is really annoying because it becomes impossible to play a game when it gets minimized by the window like every 20 seconds...The window literally appears for a fraction of a second, i cannot read the file which is running, i am unable to screenshot it. Please help. Even a solution that can just put that thing in the background(so that it runs but doesn't minimize my game) is also appreciated.
Thank you in advance.

[josseriot]

Have you tried uninstalling and re-installing Steam? Leave your Steam library as is, just re-install the Steam browser. That would be my first move.

[Black Blade]

Try to refresh Steam files
http://steamcommunity.com/sharedfiles/filedetails/?id=265037866

also if you run Task manger maybe you can freeze it to see what is that thing