Just broke the 2560 out of its unopened newly purchased package. Power up with 9 vdc source and got power light. Connected USB cable from laptop. Windows 7 immediately began process to install driver. It said it installed on COM5. Set Arduino 1.04 to the proper board and com port, open terminal and reboot Mega via on-board button. Saw something that referred to Uno in the terminal window... but thought.. oh well.. some generic pre-installed program. Dump a previous sketch that I had used on my Uno.... it transferred fine and I got output to the terminal... but not everything that I expected. At this point Win7 decided to tell me that the driver had not installed properly... (huh???) then how did I just download to it with no problem???
So now COM5 is gone, the setup for Serial Port is greyed out and device manager reports an unknown device with no driver.
A search of the site says this.... "On Windows 7 (particularly the 64-bit version), you might need to go into the Device Manager and update the drivers for the Uno or Mega 2560. Just right click on the device (the board should be connected to your computer), and point Windows at the appropriate .inf file again. The .inf is in the drivers/ directory of the Arduino software (not in the FTDI USB Drivers sub-directory of it)."
Tried the all-inclusive arduino.inf, didn't work. I located a INF file for the 2560 in the "Old_Arduino_Drivers.zip" file. It did not work either. Checked the details on the device.. and found this:
USB\VID_03EB&PID_2FEF
This is not one of the ID's show in either the new or old driver INFs. Found some messages regarding similar problems with other users.. with no apparent good solution. Made back up of INF file, modified file to show USB\VID_03EB&PID_2FEF but this did not work either (driver installed but device would not start). Uninstalled and reverted back to original INF.
So.. here I am begging for help from the masses... Please help if you can.
TJ Johnston, N4UYQ