Can't upload

Hello, I have an arduino mega 1280, was in a work condition a month back, but I was too busy so it was laying in its box. Yesterday I tried to upload a simple blinking sketch and ran in to troubles, I received this log;

Binary sketch size: 658 bytes (of a 126976 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

with this code:

void setup() {}
void loop() {}

Am using WinXP, PWR is lit green, reset button causes the initial 13 LED blink. And once I'm tring to upload both the USB LED and the 13 LED blink. Disabled the Bluetooth port driver.

Binary sketch size: 658 bytes (of a 126976 byte maximum)
E:\Documents and Settings\WiseScript\Desktop\arduino-0022\arduino-0022\hardware/tools/avr/bin/avrdude -CE:\Documents and Settings\WiseScript\Desktop\arduino-0022\arduino-0022\hardware/tools/avr/etc/avrdude.conf -v -v -v -v -patmega1280 -cstk500v1 -P\\.\COM3 -b57600 -D -Uflash:w:E:\DOCUME~1\WISESC~1\LOCALS~1\Temp\build4394417881716897745.tmp\sketch_oct19b.cpp.hex:i 

avrdude: Version 5.4-arduino, compiled on Oct 11 2007 at 19:12:32
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/

         System wide configuration file is "E:\Documents and Settings\WiseScript\Desktop\arduino-0022\arduino-0022\hardware/tools/avr/etc/avrdude.conf"

         Using Port            : \\.\COM3
         Using Programmer      : stk500v1
         Overriding Baud Rate  : 57600
avrdude: ser_open(): setting dtr
avrdude: Send: 0 [30]   [20] 
avrdude: Send: 0 [30]   [20] 
avrdude: Send: 0 [30]   [20] 
avrdude: Recv: 
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: Send: Q [51]   [20] 
avrdude: Recv: 
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

avrdude done.  Thank you.

Try this! I had the same problem:

avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

this is a fairly common error, i looked through a lot of solutions.

It seems silly, but the solution for me was so simple, though I didn't see anyone else suggest it. I just plugged my Arduino into a different COM port and it worked! the funny thing is, that I had checked the Device Manager, and the original port showed as COM5, same as my IDE was set to, but it didn't work. I plugged into a different port and it worked fine.

This should be the first thing anyone tries.

It didn't worked, it tried from port 1 to 5. I also did the loopback test successfully.

When you performed the loop-back test, which serial port did you use?

To be clear: computer --> serial port(com1) --> usb --> arduino the port is a virtual?

anyway I've tried it on port 1 and 5, both worked.

When you disconnect the Mega 1280, does com 1 disappear or com 5?

They both disappear form the ide as well as in the device manager once disconnected.

When you reconnect the Mega 1280, both com 1 and com 5 reappear?