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.