Hi everyone
I just wanted to post this on the forum because I read forum messages for hours and hours each day for almost a week before working this out. (And results from this forum show up on Google, so this might help others who are as thick as I have been...)
I was getting the error: avrdude: usbdev_open(): did not find any USB device "usb"
So I tried all the solutions on the forum and everywhere, but in the end I worked out that the problem was me! I was pressing Ctrl-SHIFT-U instead of just Ctrl-U (on Windows). (To further establish my stupidity, I was also pressing CMD-SHIFT-U on my Mac)
Anyway, so I acknowledge that there are real bugs that people with real intelligence have to fix, but for anyone who is a similar level of idiot to myself, I suggest using the correct hotkey.
I hope this helps a few others out, because oh, Lawdy, did I read a lot of forums recently...