It works sometimes but mostly never. The power is on and the screen is blank.

For anyone who still has this issue including above morris_gray,
I've encountered this myself with my first generation M-Audio Axiom 25 USB MIDI Controller plugged into a MacBook using GarageBand (G2 apparently has identical malfunction).
It should be noted that I never installed any type of software for the device, that came with the device. I simply wanted a controller for GarageBand, and I will also note that it has worked flawlessly for about 4 years on this setup, until about a week ago...

I'll provide what information I have gathered about the blank LCD screen issue as well as the controller simply not functioning correctly as listed below:
The most common way people test/fix this is to "hard reset":
- turn controller off (assuming you've kept the usb cable connected to your computer)
- hold down both the + and - buttons directly below the lcd, and simply turn the power on. Some numbers should appear on the lcd soon after the reboot and you are okay to release said buttons...
I've read testimonials, watched videos of people doing this and successfully getting their device back in action, though the reset will default anything you have saved for the device.

Sadly, this did not work on mine. I've tried several different cables- in several different usb ports- on several different computers (as suggested by M-Audio on their support page. I still get a lit up but blank lcd. I've even tried to still use it but only some awful noises come out and nearly every function just makes the thing freak out and it becomes silent/unusable/useless.
M-Audio suggests sending it back to them for fixing at this point.
Because I've had my Axiom 25 Gen. 1 for so long and I have never installed anything what so ever that came in the box, and have little faith that M-Audio will replace mine, I will most likely try to take it apart and mess around with the electronics inside as it's just a big paperweight now.
I did read that in the Gen. 1's the blank lcd could be a result of a chip gone wrong, so to speak... Gen. 2's had some type of "grounding" issue that resulted in the blank lcd and such.
I hope this helps anyone, if I stumble upon a way to fix this through my own curiosity I will inform the masses...
I'll be on the hunt for a new controller most likely and it probably wont be an M-Audio...not that I'm upset with the product, it lasted me quite a while and I've made a lot of solid songs/music with it, but rather I feel the need for something different and maybe a little more sturdy that can actually be a synthesizer on its own, not just a controller.
- Christoffer