A peculiar puzzle is it dreaming or something?

please forgive me this is rather a long story and a peculiar one.

I'm running windows XP home on an 80 GB hard drive with the maximum amount of memory that XP allows and I have two 1 TB USB hard drives attached to it, both made by Western Digital, one with a blue light and one with a white light.

The other night I shut down my computer and switched it off at the mains and I was sitting very quietly reading a book when I heard a whizzing noise and looking up I saw that the hard drive with the blue light was making that noise.

what puzzles me is that the entire computer was shut down; what on earth was blue light, if I can call it that, Doing? – Was it dreaming? And why would it do it? The whole computer was shut down and switched off at the mains although obviously not the USB hard drives; the other one which I will call white light, was perfectly quiescent but blue light kept running up to speed and flickering – is that strange or what?

I should say that when I switched the computer on the next morning both USB hard drives were working perfectly happily and seem to be working perfectly happily to this day.

I'm probably, as usual, being completely stupid,but what would make blue light do whatever it's doing?I expect you frightfully clever chaps who know all about these things probably think that it's perfectly obvious what it's doing, but I am dammed if I can;the only thing that I can think of is that it's dreaming, but I'm perfectly certain that computers or USB hard drives don't dream, but maybe I'm completely wrong.

I should add that both USB hard drives have their own power supply both were switched on and had power to them; certainly blue light must have had power to it or it could not have had a blue light on or be whizzing away as it was.

I was wondering, should I switch them both off or would that hurt them? I've heard of people having problems with external hard drives when they are switched off or disconnected suddenly or somehow
I use the hard drives to backup and store all my music and pictures and documents and I would be very reluctant to lose all the stuff that I've got on them. in a manner of speaking one of them backs up the other, in case one of them goes down.

I'm very sorry to waste your time for the sake of idle curiosity but it is a puzzle and I'll be fascinated to know why blue light is doing what it's doing and moreover what it is doing,always assuming it's not dreaming Hell, for all I know they need to dream from time to time like we do.

Can I just add that because I am only one handed I have to use a dictation program and sometimes it misunderstands or mistranscribes what I'm actually saying,so forgive me please if some of that came out looking rather peculiar;half of my brain does not work and it tends not to notice mistakes.

I don't know, but I'm curious!
Can hard drives dream...?

I was going to go with Capacitors,CMOS battery, and or router-less cable modem connection.....but I like yours better.

do androids dream of Technicolour sheep? The point is that the main PC is shut down correctly and switched off at the mains, so that I can't think of anything that could be affecting blue light, however, I will try switching off the router/wireless modem and see if that stops it; I suppose the only solution to these things is systematic trial and error. Blue light doesn't make a very loud noise and I doubt if anyone who wasn't perfectly quiet and still inside could, possibly hear it's whispering whizzing sound. what the hell,there are more ways of skinning a cat than drowning the bastard and if I want to sit quietly undisturbed I can always go and sit in another room, but I was just puzzled

The point about the "router-less cable connection" is that a router affords security, otherwise being hooked into the Internet is an unguarded path into your computer. the other things I listed are things that store energy (capacitors) after the power is cut.

forgive me, please. If this is a very stupid question, but how can the computer be connected to the Internet. If it is switched off, shut-down. If it was switched off, and no longer connected to the mains?

Oddly enough, and I'm grateful to you. I was about to ask a question about whether I was being naive in thinking that my computer was perfectly shut down and switched off at the mains?because I am short of money and have a thing which tells me how much it costs me per kilowatt hour to keep the computer is switched on, and because I'm tight-fisted, I always religiously switch it off completely.when I go to bed, or go out for any significant length of time