Leaving computer on all time puts excess wear on mechanical components (the hard drive spindle motor and cooling fans). Best compromise. First user in morning turns it on; last user turns it off. We leave our desktops on all time allowing for scheduled utility tasks to run during overnight hours. We also restart systems (to flush RAM and reset operating system) on a regular basis and routinely remove case covers to clean out any dust that may have accumulated, especially around fans and screens.

#3 -- Stop Popups! Never click inside window of a popup. Instead, close it by clicking on X in upper right corner. Many people are fooled into installing spyware applications by popups that promise to clean their system. If you receive a message saying it can help, assume it’s spyware and don’t click!