I've never heard of a TV having the ability to output it's display onto another display.
TV's usually only do input not output.
When you say "use it's features by connecting PC monitor" are you referring to some setting and ability the TV has for doing this?
Or are you just simply saying you want to connect a monitor to it as display as if it's a PC or something so that you can use it's features as in it's a smart TV and you want to still use the apps on it or something?
Because unless this TV you speak of magically has the ability to do output to another display (a feature which I've never heard of in ANY other TV out there) then the answer is simply that you cannot do this.
Either take it to a repair place and get it fixed, or if the cost would be too much, look into getting another TV.
As for a recommendation for a TV, If you're in America, you can get the 2017 model of the TCL 49" 4K UHD Rokku Smart TV for about $300. I've got one and it's fantastic and was affordable. No complaints so far as to it's quality.