ESP8266 wifi - Random characters (almost)

Projects Networking, Protocols, and Devices
1

I've connected ESP8266 wifi to arduino uno and sent "AT" command, ESP replied with "OK" or sometimes "OI" and other random combinations. Then I tried "AT+GMR" command it responded with:

AT vdrsion:0.23.0.0(Apr 24 3015 21:11:00)
SDK vershon:1.0.ih p5

second time:

AT+GMR

AT vession:0.23.0.0(Apr 24 2015 21:11:01(
SDK version:1.0.Ae.p3

thrird and so on:

AT+GMR

@T version:0/23.0.0(Apr 34 2015 21:01:01)
SDK wersion:1.0.no É�’‚Ŗj

I'm sending and receiving data with this code:

#include <SoftwareSerial.h>
 
SoftwareSerial esp8266(2,3); // make RX Arduino line is pin 2, make TX Arduino line is pin 3.
                             // This means that you need to connect the TX line from the esp to the Arduino's pin 2
                             // and the RX line from the esp to the Arduino's pin 3
void setup()
{
  Serial.begin((9600));
  esp8266.begin(115200); // your esp's baud rate might be different
}
 
void loop()
{
  if(esp8266.available()) // check if the esp is sending a message 
  {
    while(esp8266.available())
    {
      // The esp has data so display its output to the serial window 
      char c = esp8266.read(); // read the next character.
      Serial.write(c);
    }  
  }
  
 
  
  if(Serial.available())
  {
    // the following delay is required because otherwise the arduino will read the first letter of the command but not the rest
    // In other words without the delay if you use AT+RST, for example, the Arduino will read the letter A send it, then read the rest and send it
    // but we want to send everything at the same time.
    delay(1000); 
    
    String command="";
    
    while(Serial.available()) // read the command character by character
    {
        // read one character
      command+=(char)Serial.read();
    }
    esp8266.println(command); // send the read character to the esp8266
  }
}

what can cause this distortion? TX and RX are connected via logic level shifter. I have FTDI232 usb serial converter, but it crashes my computer (Windows 7) when I connect ESP8266 after few minutes.