text: which is the safest mode to leave the pc in ovwrnight,hibernate or stand by and is security still at 100%? my power bill has risen since i was told the safest way to protect my pc is to leave it and the printers on 24/7.  secutiry scans and system upgrades are scheduled for late evenings so as not to inrerfere with work. if i understand corectly i will conserve in both stand by and hibernate.i also understand hibernate to be of the greatest savings value.i would like to know if scheduled security sweeps and upgrades will also be performed in this state of sleep?also is microsoft able to install recommemnded upgrades durring this state?briefly stated is it recommended to leave the pc in hibernate? actually, it isn't better to leave your computers going 24/7.  while it will make your power supply last longer, everything else will wear out faster, and your electric bill will roughly triple.  well, your computer's portion of it will, anyway.  also, you're much more likely to need to buy a whole new "rig" sooner if it's left going 24/7, because computer components are sensitive to voltage peaks/spikes, but only while they're running.  they will experience 3x the voltage peaks/spikes if they run 24/7.