Problem with Freeduino Mega, ethernet shiled, tft ST7735 and SPI

Projects Networking, Protocols, and Devices
4

The w5100 slave select is digital pin 10 on any Arduino.
Change your setup to disable all the SPI interfaces first.

void setup() {
  
    // disable w5100 SPI
    pinMode (ss, OUTPUT);
    digitalWrite(ss,HIGH);

    // disable TFT SPI
    pinMode (ss1, OUTPUT);
    digitalWrite(ss1,HIGH);

    // disable SD SPI if using an SD card
    // pinMode (4, OUTPUT);
    // digitalWrite(4,HIGH);
    
    Serial.begin(9600);
    // join I2C bus (I2Cdev library doesn't do this automatically)
    Wire.begin();
    // start the SPI library:

    while (Ethernet.begin(mac) != 1)
    {
      Serial.println("Error getting IP address via DHCP, trying again...");
      delay(15000);
    }
    // the Ethernet.begin() function leaves pin 10 LOW (SPI enabled), so back to HIGH
    digitalWrite(ss,HIGH);

    // rest of your setup stuff

Does that do any better?