I've sat down in front my computer and found that it has rebooted. I was not using the computer at the time. I leave my computer on 24x7. The last thing I changed was adding "Microsoft Security Essentials".
The whole hard drive is encrypted with TrueCrypt.
Here is the error I got once I logged in
Resource and Performance Monitor notes the error "The device, Photosmart C6100 series, is disabled. If this device is no longer used it may be intentionally disabled. The Plug and Play ID for this device is ROOT\MULTIFUNCTION\0000."
It also says "...has not recorded and anti-virus product." I thought that was what "Microsoft Security Essentials" was.
Thank you for your help.