Arduino does not program and the RX light just flashes

Development Tools IDE 1.x
1

Hello,
I am trying to upload a program in my Arduino Uno R3 and it just blinks the RX light.
And I am getting this long error.
Please help me with this.
Thanks,

Sketch uses 1,112 bytes (3%) of program storage space. Maximum is 30,720 bytes.
Global variables use 13 bytes (0%) of dynamic memory, leaving 2,035 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=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
2

Check your drivers for your USB/Serial chip. Try the Loopback test.

3

The drivers are ok. I tried loading another Arduino UNO and it works.

4

I also did the loopback test and it works fine...

5

Maybe bootloader is missing. If you have UNOs in DIL version, try to swap Atmegas and test. The bootloader you can upload with the second Arduino using it as ISP programmer. Look at Arduino ISP in Learning.