Is it harmful to my pc if I shut it down first then pulling the power cord?

Answer 1

It's potentially harmful. Although the PC is powered down, the cord is still live as is the power supply unit (PSU) attached to it. Removing a live cord could cause an arc or power surge that may be harmful to the PSU and/or the computer itself. Most PCs have a rocker switch on the rear of the PSU (near where the cord is attached). This should be switched off once all disk activity has ceased and the power LED has gone out. You should also isolate from the mains supply before removing the cord, although it's good to allow a second or two for any residual charge to fully drain to earth. Reconnecting the cord is the reverse procedure: connect the cord to the PSU and to the mains (both of which should be off). Switch on at the mains, then turn on the PSU with the rocker switch and finally power up the computer itself.

Note that a PC often have several power states. Hibernation mode is similar to shutdown except the contents of memory are copied to a mass storage device which may take a little longer than a normal shutdown. Other than that they are both the same and the computer can be isolated from the mains once hibernation is complete. Restarting from hibernation should be quicker since the majority of the boot process can be completely bypassed. Standby mode is where the computer shuts down unused components to or conserves power by entering a low-power state, but never completely shuts down (there may be several states depending on which components are powered down and which are in a low-power mode). Do not isolate the computer from the mains whilst in standby mode as the CPU is still active and there may be occasional writes to the hard-drive by programs running in the background.