I have tried to upload several of the sketches by Arduino.They compile fine but on upload give the following message: I am using the M2560 starter kit.
"avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
Upload error: Error: 2 UNKNOWN: uploading error: uploading error: exit status 1"
Help please, thank you all