Arduino Uno (clone) error: "Programmer is not responding"

So I bought an Arduino UNO clone from eBay, it looks identical to the normal UNO, but without the logo. I set it up, following my friend's advice, setting the COM port to 3, selecting the correct board, making sure the drivers were up to date, etc. and started writing the "blink" program. But surprise-surprise, it's not working. Here is my code

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
  delay(500);
  digitalWrite(13, LOW);
  delay(500);
}

When I run this code, this is exactly what happens TX flashes 3 times, L flashes 5 or 6 times, L goes solid. On the IDE, it still says "uploading..." After around a minute, the console spits out a bunch of orange text, saying this... Sometimes it says COM3 isn't accessible, other times it just skips that and fails to upload regardless.

Sketch uses 1,030 bytes (3%) of program storage space. Maximum is 32,256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 bytes.
avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.


Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x53
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x53
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

I have no idea what to do.. I don't even know what any of this means. I've tried looking up all these problems, but nothing seems to be matching this problem.

There's no point returning it (postage costs) and I don't want to get a replacement. Does anyone know what I should try? So far I've tried deleting the drivers and reinstalling them, pressing the reset button during different times (startup, idle, upload, after upload failed) but nothing seems to be working. Please help :(

EDIT: Don't worry, I just bought a new one and it works fine. It was a one off error with the USB-Serial converter.