Thanks CPT--There isn't an error msg. The computer was in sleep mode and when I woke it up, there was the blue screen made up with tiny blocks. Looks like a distorted normal screen.

I asked my daughter to look at it and her immediate response was: oh no, you've got the blue screen of death. She's had it twice work. It grows slowly. Takes about two months to kill the hard drive.
You can still use the machine until it dies, but run the risk of spreading it. It is considered an infection of the hard drive as opposed to a virus. Norton doesn't help and ccleaner doesn't help.

In all my years, I had never seen it or talked to anyone who got it. Not considered a virus.