programmer is not responding

i received this error message:

Arduino: 1.5.7 (Windows 8 ), Board: "Arduino Uno"
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x01
Sketch uses 4,170 bytes (12%) of program storage space. Maximum is 32,256 bytes.
Global variables use 222 bytes (10%) of dynamic memory, leaving 1,826 bytes for local variables. Maximum is 2,048 bytes.
avrdude: ser_open(): can't open device "\.\COM5": ‏‏הגישה נדחתה.

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

someone know what is the problem??