One of my systems here in the house is playing up. It has run like it is for a couple of years, I've not added anything new, hardware or software. It has an MSI mobo with a Core 2 processor, 2GB RAM. a regular hard drive - usual stuff, running under a fully updated XP. Normally, it runs 24/7 as a BOINC cruncher. I connect a screen to it once/twice a day to send whatever BOINC work is finished home, then take the screen off and largely forget it.
A few days ago, it was "apparently" switched off. I had not done this, but it had that look about it, fans stopped, only a single LED on the mobo showing instead of the usual christmas tree it usually has.
I connected a screen, and switched it on. The black and white initial screen appeared, then the Windows XP start-up screen, the one with the moving "light" below the centre of the screen, under the XP logo. The disk activity lamp flickers away as usual. The screen goes dark as it usually does before it asks me to log on, but it never does. The screen remains dark. The disk activity lamp is off, and it sits there, and sits, and sits. It makes no sounds, (well, apart from the obvious things like fans).
Since it is getting that far, I assume the processor, mobo, video, disk and memory are all okay. So, what's up here?