<p>Just because you can leave a computer on safely doesn't imply that you should. You will save $$$ by leaving them off.</p>
<p>There is more than on and off when it comes to Windows:</p>
<p>1- ON = The computer and monitor stay on all the time. The monitor is bright (and uses up lots of electricity if it is CRT) and they computer fan can be loud (depends on computer)</p>
<p>2- MONITOR OFF = I have all my computers turn off their monitors in 15 min or less, unless I am watching a movie. Also helps prolong monitor life.</p>
<p>3 - STANDBY = Monitor is off, fans may or may not spin (depending on computer), and power is going to memory and processor (but very little). Allows computer to resume very quickly.</p>
<p>4 - Hibernate = The computer saves all of it's memory to it's hard drive then shuts off cold. Uses no power and can resume by loading the memory back from hard drive. Boots much faster than a regular startup.</p>
<p>5 - OFF = Windows (and then all of your background programs) load fresh. Recomended if your computer is slow or has little memory.</p>
<p>Turning off your computer constantly can harm it because as components cool and heat up they expand and contract, which can cause damage over time. Keeping it on keeps the components warm which minimizes this effect. The thing is it would take a long time for the effects of contraction and expansion to have a real effect on components (likely longer then the life cycle of your typical machine) so it doesn't matter in most cases unless you turn it on and off like 20 times a day or something like that. However keeping it on 24/7 also can strain the components, but again you're not really going to hurt it since the effects would take literally decades to have an effect. The best balance IMO is to turn on your computer the first time you use it and just keep it on until you go to sleep. Keeping it on all the time won't cause anything horrible to happen though so if you want to go for it. Energy is still really cheap (especially here in the good ol USA) so I wouldn't worry too much about saving (well unless you want to save or you have power grid issues like many places in CA or right now NYC lol) especially if you have a laptop...if you want to calculate cost per day 350W is a typical useage figure for a desktop, 65-90W for laptops. If you do keep it on it is a good idea to restart at least once a week.</p>
<p>over the past few years, i've left my desktop on for days at a time, up to about a week. yes, i'm running windows (zomg!). performance doesn't noticably decline (running on 768 MB of ram, but not sd or ddr).</p>
<p>it may have fried my graphics card, though. i've had to replace that single part three times now and this is the only solution i've been able to come up with. keep the heat down and i think you should be fine. </p>
<p>oh i had power supply trouble, too, but i don't know if it the fan died, if it died, if it just wasn't supplying enough power for my machine or what. may be related.</p>
<p>something:</p>
<p>Are you running a name-brand PC or a 'home-built' or off-brand built at a small computer shop? I ask because I've noticed that power supplies and fans from the name-brand manufacturers seem to be of much better quality than any of the aftermarket ones (this is after dealing with many hundreds of both types of systems). Also, the cases need to be engineered for cooling. Many of the aftermarket cases, even if they look great (uv lights, etc.), aren't well engineered in this area. It's not normal to have a graphics card fail that much but they definitely need cooling - especially the higher-end ones with heat sinks.</p>