[Oxymoron238]

When you connect it to the pc in the bootloader mode, it should say USB in the white color area instead of serial.

If you can get it to do this, then try opening up your task manager (ctrl-alt-delete) on your computer and closing some of the processes there. If you see Googleupdate as a process, close this and then try to flash the rom to your device. When I did this, my flash ran perfectly. (by the way, restarting your comp will bring the processes back, so it shouldn't be a huge risk to your comp, but just in case, do this at your own risk!)