No, except in exceptional circumstances, such as a power failure.
Ruin seems quite a strong word! Modern PCs are designed to cope with sudden power-loss - for example during a power cut, but it isn't recommended to simply power a PC off as any applications that are running won't save their work and the operating system won't be shut down properly. There's also a chance that the hard drive(s) could be damaged as their heads won't be parked properly, although modern drives are designed to be self-parking.
turning the computer off
It allows the computer to reboot.
e monitor
Basically turns off or hibernates your computer.
Reset
A computer can not turn off by itself. The monitor just turns blank it you leave it. To turn off the computer you have to prees the on button on your computer. If you press the botton on the monitor it is not turning the computer off... just the screen.
No, use the power button to turn off your computer. USB is best because You can unplug and plug the keyboard back in without your computer turning off.
A power cycle is turning off and turning back on any electronic device.
Do it would be the general way forward. To prevent this happeneing again. Make sure that you are turning the computer off from the windows start icon in the lower left corner. Do NOT turn off the power to the computer from the mains. Refrain from turning off the computer from the power button
No but it can ruin other parts of the computer like the harddrive.
USB.
Well it ruins a computer cause it's like water and can get in side of the computer and ruin the insides.