My Arduino was working fine all day, as it has for years. I disconnected USB cable, added an Ethernet shield, connected the USB cable back and I could no longer connect via Serial Monitor. I disconnected the Ethernet shield and it worked again. Connected the shield and it went back to no connection. COM3 was in the Device Manager, everything looked like it should work but the IDE was telling my COM3 is not available and Tools/Port menu was greyed out. Did this a couple more times, then thought I would restart the computer with the shield attached. Now I still cant connect in the IDE and have no entry in Device Manager anymore.
The internet tells me its the firmware on the MEGA8U2. Seems odd as before the restart it worked without the shield. In any case Arduino's help page is super useless. The link's broken but FLIP isn't too hard to find. However touching the pins on the header doesn't seem to do anything and there is no option to simply "upload the hex file" as the page suggests. There is also no option for MEGA8U2 or even AT90USB82 as this guy's video shows in FLIP.
Speaking of that guys video, I follow his instructions to get the device into DFU mode, which are different than the other page's. The lights flash but I still get nothing in the Device Manager like he does in the video. Even if I did, FLIP doesn't have AT90USB82 listed as an option for me anyways like it does for him. Maybe it shows up after drivers get installed but I can't do that since it doesn't show up in the Device Manager.
Does anyone have any thoughts on how to get this thing working again before I throw it out?