I turned on my MacBook Pro this morning. It took a bit longer than usual for the screen to light, but it eventually did. What was odd was that the default desktop picture was on my desktop instead of the one I've had up for weeks, the date/time were set to January 2000. Possibly related was the fact that it wouldn't recognize my AirPort Extreme router. I fixed everything and have not run into any other glitches yet, but am wondering what the reason might be for this sort of a reset. Viruses?

Any help would be appreciated.