Not sure if programmer or ATMega is burned some time ago i tried doing this with my original arduino uno r3. I guess i had to plug the power cables in wrong order(i think it's called reversing polarity)  because my arduino stoped working. It turns on (the power diode is on) but i cannot upload any sketch on it. I'm thinking about changing the ATMega chip but, before i do that i want to be certain that it's the chip issue ,not the programmer. I have another arduino uno, and i heard that i can upload sketch with it to another uno. So my idea is, if i do this i will be able to say whether it's the programmer or the chip issue. The only problem is that i don't know how to do this and i wasn't able to find any reasonable tutorials online. Please tell me what to do.
Many Thanks,
Jan
The Arduino IDE ships with a built in ArduinoISP sketch, and there is a very detailed tutorial with wiring diagrams etc on the Arduino site.