Mbox 2 - dim LED's, only half bright and no sound

[Bradleystyles]

Hi, I have a Macbook Pro, Mac OS X version 10.5.8 and I'm running Pro Tools LE 8.0.4

I've had my Mbox2 working with my Macbook pro fine for several months, no problems. Today, all of a sudden, when I connect my Mbox2, the USB light no longer lights up, and the only sign that it is connected is that the two 'Mic' LED's appear to be half lit, about 50% as bright as they usually are. And there is no sound output to my monitors, my mac does not seem to recognise the Mbox2 in any way.
I have not done anything different, I have not made any upgrades or anything. Any ideas why this has suddenly happened?

I'm imagining it's some problem with power, it seems like the Mbox isn't getting enough power, though it is connected to my powered USB hub, just as usual.

Even when I remove all other devices from the USB hub, the problem persists.

Any suggestions would be a huge help,

THANK YOU

[Bradleystyles]

P.S. I have also tried plugging the Mbox2 directly into my Macbook pro, as well as using different USB cables; the problem is still there, ruling out there being a problem with the USB port or cables

[Bradleystyles]

I've also just tried reinstalling protools LE 8.4, and the problem is still the same