I have a HP mini netbook running Windows 7 Ultimate.
I usually leave it running with the lid shut and connected to power. This worked well for two years.
For the past few weeks, I usually find the mini displaying the text "Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key".
Apparently the mini decides to reboot and forget its boot drive.
Switching it off and on eventually results in the mini booting again.
Any idea why this happens? There seems to be nothing special in event viewer.