Anyone know the secret of uploading to Mega2560 ?

[SmokeHertz]

Sorry to start a (newbie :-/) new  post on what is probably out there somewhere but I (and even my supplier) can not find clear instructions for uploading to the Mega2560. Like others who have posted, I have success with the Duemillanove (simple via port and driver) but get in a real mess with the Mega. It seems that the .inf file is to be used not the driver. How do I install the .inf  file? Also because the upload error message shows (e.g.) COM 3 already in use, this suggests the software is still trying to use the other method. Would anyone have a link to CLEAR instructions or would like to write some for us all? Also I read that there is an optional separate upload hardware device available (similar to JLink). This apparently avoids use of the boot loader. Anyone using this? Thanks.  

[curtishorton02@yah]

Don't know if this is your issue or not, but I had something similar and this is what I found that worked.

http://forums.adafruit.com/viewtopic.php?f=25&t=17769

[SmokeHertz]

Thanks for that. I will try a reload but I feel it's the board firmware on the Atmega8U2 because my system (Windows XP) does not recognise the USB as a valid device. Instead of giving the 'beep' for 'USB recognised' it gives a different 'double beep' sound which suggests that it is trying but finds it invalid.  I am having so much success with the Duemilanove and several shields that this has gone on hold for a moment. I will look at how to re-upload the firmware in the 8u2 but also consider building an ISP programmer which could be fun. Just strange there is not much on this yet. Will update soon.

[mellis]

Did you try going to Device Manager and updating the driver for the Arduino device listed there?  Point it to the drivers/ directory of the Arduino software.