Nexus 7 Fastboot freeze on USB connection

I never thought I'd have to go as far as create a thread pleading for help, but after a lot of Google searching I still cannot find someone with the same problem.
I will explain:

I am trying to use fastboot, which I (don't think) I've any problems with in the past.
I can issue commands in normal use via adb from my PC fine.
I can adb reboot bootloader ok, and can get into the bootloader any other way just fine.
I can use the volume keys to navigate the options in the bootloader just fine.

The problem comes with I connect the USB to my PC whilst in fastboot.
Windows fails to recognise the device, and says it may have malfunctioned.
It won't allow me to reinstall the drivers successfully it seems, and seems to have a problem with the USB Host Controller too.
Fastboot immediately freezes, and I'm unable to even navigate using the volume keys, let alone issue commands from my PC.

My question then is twofold:
1. Is there likely to be a problem with the USB port on my device, or some sort of bootloader corruption?
2. Is it possible to return to stock Android without using fastboot?

Finally, I would like to stress that I've seen plenty of similar looking threads, but it seemed that the posters of those threads merely had problems getting in to the bootloader or recovery.
I haven't got that problem, the problem only arises when a USB is connected to the PC, the tablet becomes unresponsive only in bootloader mode.


If anyone has any advice to offer at all, I'd greatly appreciate it.
Additionally, if the problem is solved, I will post a detailed set of instructions in case anybody else should encounter a similar problem in the future.

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Update for anyone who happens to read this in the future:

[This guide](http://forums.androidcentral.com/ne...3923-guide-nexus-4-factory-image-restore.html) has a useful FAQ at the bottom which helped a little.

I think I managed to determine the problem was likely a duff usb connection, either on my Nexus or on my computer.
I was able to just about hobble through by keeping the cable in the same place.

In case it wasn't just this, this is what I did:

1. Flashed TWRP recovery from their app.
Went into bootloader and failed to do anything

2. Flashed CWM recovery.
Managed to be recognised in fastboot.
I still had problems with my Nexus 'malfunctioning' -- possible the USB.
I updated the drivers using the ones from [this thread](http://xdaforums.com/showthread.php?t=2588979).

3. Flashed a new bootloader image immediately (there were rumours that a dodgy version had been released accidentally). [This](http://www.androidfilehost.com/?fid=23060877489996594) is the one I used.
Then I managed to get the stock ROM flashed, and the bootloader locked up again.