you have to create a power profile that does not turn devices off to save power. The system will try to save power by shutting off the mouse, keyboard and display, etc... This can be disabled in the power profile set up.
Click start, control panel, hardware and sound, Power Options.
I've never been a big fan of those power save modes, Suspend/Hibernate as they never seem to be consistent 100% of the time. Did you have to pull the plug to get the power back on then?
As soundguruman mentioned, get to the control panel and power options and you can get into a custom power mode or you can modify an existing power mode. If you do want the system to go into a suspend mode or shut down hard drives/monitors you can customize all of this in that section.