[H] vista64 keeps turning off my scanner

[Winterlight]

All of a sudden Vista keeps powering off my scanner. It is a HP USB 
and it is using basic native Vista 64 drivers. Up until a couple of 
weeks ago it worked fine. the blue light always stayed on and the 
scanner was always ready when I was. Now the blue ready light goes 
off and I have to unplug it and plug it back in, or reboot in order to use it.

Nothing has changed in my power management settings, which only 
effect  the monitor but Vista keeps turning the scanner off. Any ideas?