You said transferring from C to D. You said you have not attached any hardware, so what is D: ?
Usually of course it is a a CD/DVD drive. If so in this case, what were you using to transfer the files to a CD or DVD?
Many don't consider a USB hard drive to be hardware. But if this is a USB external hard drive, do you normally keep it connected and running when you shut down/start up? If so, try safely removing the hard drive before shutting down.
Server? Tell us more about that.
My initial thoughts: Copying files to CD/DVD using Windows drag and drop may have still been in progress. Or a USB hard drive may be failing.
Glad to see it appears to be working now, but obviously 'something' happened.
I'm not quite sure how to describe this so I can't do an effective search. I have a fairly new laptop with Win 7 Pro, 3 GB RAM, I think I have all high priority updates installed. According to the Control Panel the last program I installed was Google Earth on 1/28 and the PC has been running fine since then. I have Windows Security Essentials for AV. I have not attached or removed any hardware.
Last night I tried moving some music files from C: to D: because the laptop has a relatively small HD. The system seemed sluggish but I assumed it was because of the background copying. The situation did not improve after the copying finished so I rebooted. Shutting down took over 20 minutes and seemed to hang at the "Windows is Shutting Down" screen. I finally forced a power down by holding the power key for several seconds. This morning when I turned the PC on it took about 20 minutes to boot (usually about 30-40 seconds) and ran very slowly. Firefox took about 15-20 minutes to load. Task Manager showed low system activity. I eventually decided to reboot. Shutdown took several minutes, but the restart was more-or-less normal and everything seems normal since then. System performance seems OK even though I'm running a backup to the server in the background.
I've never seen anything quite like this before. I don't have any reason to suspect malware (though I am running a scan). As best I can tell there were no new updates installed overnight. So far I have not found anything that looks 'off'.
Any thoughts or suggestions for testing? I'm not one to believe in spontaneous healing of computer problems, so this troubles me, but I don't know how much looking I should do if the system seems normal now.