Just to relate my tale of woe: My computer has been acting up for a long time...freeze ups,. fails to wake from sleep, etc. I assumed possibly Vista corrupted and needs reload, poss. bad memory; finally found a Tech Shop I had some confidence in....they determined the Mother board was causing power glitches. new board, $130 out the door....I am happy camper!
I have been extremely frustrated by the same problem which has been happening on the desktop since I bought it in late 2009. It runs Vista 64 bit. Turns out the problem was caused by my Maxtor external drive which I use to backup my files. Since I now plug in the Maxtor only when I want to back up or retrieve, the problem seems to have gone away. Yesterday, I plugged in the external drive and then got distracted for a while; long enough for the computer to go to sleep. Sure enough, when I "woke up" the computer, a few minutes later, I got the blue screen with the usual "driver power state" error!!! So, either I buy a new external hard drive or remember to unplug the one I already have.