Eugene's observations

I'm thinking that many people would rather have their laptop PC switch off when they click the first button on the Go/Start button rather than Sleep. In 'sleep' mode the current state of windows is preserved in memory (unlike hibernate mode where it is saved to disk). So if power is lost, your Windows system crashes and is potentially corrupted (as open files are not flushed from volatile memory).

To change the default behaviour visit the Control Panel and select
Power Options
Change plan settings
Change advanced power settings
Power buttons and lid
Start menu power button
Click 'sleep' and change to reflect your preference.