Arduino Uno - Serial Communication Problem

No I didn't say that.
You asked:-

guys, how do you physically connect tx/rx pins to your PC?

and I told you.
Now you are asking about alternative TX/RX . The answer to that one is simpler.

  1. Have you got a serial port on the PC - Yes use a MAX202 to connect it up - if no the go to 2:-
  2. Get a serial port on your PC by a USB to RS232 serial adaptor cable and go back to 1.

I was talking abut these TX/RX pins!!! Since the beginning!!

#define rxPin 2
#define txPin 3

And anyway I don't actually need to connect Arduino to PC again, besides USB: I'm interested on using TX/RX pins to connect Arduino to serial-controlled devices, and I can't find any MAX232 in electronic shops here around.