Before everything, let me state that I am a complete beginner trying to use arduino.
I am using Arduino Uno with ATMEGA328p.
I have been trying to make a program that would have as an output some kind of a timer displayed on a Serial 7-Segment Display. (https://learn.sparkfun.com/tutorials/using-the-serial-7-segment-display/7-segment-shield) At first, everything worked nice, I was getting accustomed with the IDE and the microcontroller programming, trying different programs. The first program I used to make the Arduino with atmega and the display communicate was https://github.com/sparkfun/SevSeg/blob/master/Libraries/SevSeg/Example/SevSeg_Counter/SevSeg_Counter.ino which worked fine. Then I starded modifying the program in order to get accustomed with this type of programming. I guess I did something wrong at the declaration of the pins that were connected to the display, because when I uploaded the modified program onto the board, the display showed 0000. Since then I have tried everything to make the shield display anything, at least the first tried program, but it won't display anything but 0000. I even bought another ATMEGA328p and another shield, but whenever i try to upload the program from above, the same thing happens : 0000 is displayed.
Is it possible that I have done something to ruin the board? Does anybody happen to know what the problem is and how can I fix it?
Thank you very much!