can no longer upload programs to my arduino uno

Hi I'm relatively new to Arduino. I have an elegoo uno r3 board, which used to work but will no longer allow me to program it.
When I attempt to program I get the following message:

Arduino: 1.6.9 (Windows 10), Board: "Arduino/Genuino Uno"

Sketch uses 2,432 bytes (7%) of program storage space. Maximum is 32,256 bytes.
Global variables use 66 bytes (3%) of dynamic memory, leaving 1,982 bytes for local variables. Maximum is 2,048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x9c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x9c
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

my operating system is windows 10
and I have already looked through the common reasons for this error and have checked that my port and board are correct in the IDE. I have also tested the board using a different computer and the same error occurred.
This leads me to believe that ive damaged my board.
Any help will be useful
thanks,