Programmer is not responding, not in sync

Whatever sketch I open or create, from whatever source, it fails to upload with a whole raft of errors. Here's an extract of them:

System wide configuration file is "C:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf"

Using Port : COM3
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xc6
avrdude: stk500_recv(): programmer is not responding...

Programmer is not responding, not in sync