Having trouble getting your computer to turn on? There are several things that can cause this. There are also several variations of what people call "not turning on."
Is it getting power? Of course you'll want to check the obvious. Did a power plug become pulled out? Does the power-strip work? Try a light in the same outlet to be sure your outlet is working.
Is anything happening when you try to turn it on? Does it load and show anything?
Do you have any strange clicking noises from the machine?
For Desktop & Laptop Users:
Make sure the monitor is on and that the power button is clicking on. Do you hear any motors turning on?
If it's turning on but the screen is dark, you could have a faulty monitor. Check the plugs in monitor and the end that attached to your computer. If you have a spare monitor, try using it.
Try holding down the power button for 10 seconds to try to power down the system. Wait a moment, then turn it back on.
If you get to the Windows screen, but can't get any further, see this article.
If it loads to a screen with strange wording, a blue screen, or loads to a blinking curser, you may have a more serious issue.
For Laptop Users:
Be sure you are plugged in or that the battery is charged. Are any lights illuminating? Try holding the power button for 10 seconds to try to power down the system. Wait a moment, then turn it back on.
Try a second monitor by plugging it into a compatible jack.
Try removing the battery, hold the power button down for 10 seconds, reinstalling the battery, plugging it in and powering on. This resets the BIOS memory.