Anybody here with similar problem?

I started having problems with WiFi. It indicates that it is on, but when browsing the Internet, or watching movie via UPNP, or when using any application needed Internet, it stops working although the icon indicates that I am still connected. Pages stop loading, movies stop playing, UPNP is unable list my files, and BrighHouse TV app just freezes. I have to turn wifi off and back on to somehow reestablish connection. That helps, but only for a few seconds or minutes.
I tried hard restart and somehow wiped out the entire tablet. Still, it does exactly the same after installing just a few apps.
Today morning BrightHouse tv was playing but it stopped. I just turned it off, but in 10 minutes or so the app started playing suddenly. So, the connection reestablished itself though it took forever.
I have no idea if this is something with my router, or if this is something with the tablet. My (wired) pc works fine. Other laptops seem to be OK.
Any idea?