If, like may folks here on these forums, you get stuck with a blank display and no other lights after an attempted Line6 Monkey update- and the support folks suggestion of a soft reset doesn't work- DON'T WORRY YET!
I figured it out- and I hope the Line 6 people add this to their troubleshooting guide. Here's the deal- they warn you about plugging into a USB Hub- you may be plugging into a "Hub" without even knowing it. I think that's what happened to me. I thought a "hub' was some kind of external device for plugging a bunch of USB devices in. I was plugging straight into my computer so I figured, no problem.
When I got the blank screen issue, I tried to install the USB driver manually through Device Manager but to no avail...it never recognized the XT Live device and would not allow me to install the newly downloaded driver. Finally I noticed through Device Manager that the "unknown device" was on a USB "Root Hub". I unplugged it and plugged into a USB 2.0 on the BACK of my computer, and unplugged all other unnecessary USB devices for good measure. Next thing I know it seems to be doing something different, recognizing the device, asks me to reboot the computer, and then the Windows hardware setup wizard starts in and it now knows that I've got a Line 6 Pod XT Live and, installs it (plus some extra packs that I guess I was eligible for!), and my display is BACK and all the lights are working. HOOORAY!!!!
So- ignore those "soft resets" etc. that don't work. Plug it into a different USB port (preferably one in the back) and your machine will probably come back to life good as new or better.
I am so relieved and I hope this message gets out there before other people freak out and pay for needless repairs or start trashing the Line 6. The support techies should have figured this out but I guess they think everyone knows what "USB Hubs" are and how to avoid them.
Better yet, Line 6 should fix the Line6 Monkey software so that it doesn't just hang in the middle and wipe the XT Live system when confronted with a USB Hub.