|So is it hot boot/cold boot as your subject line asks or hard boot/cold boot as you ask in the body of your posting?|
If the former, then to add to jefro's posting, a warm boot for a PC is when you choose 'restart' from the windows shutdown menu. Or CTRL-ALT-DEL from dos. With a warm boot sometimes hardware, especially PCI devices, aren't reset. As far as I know hot boot and warm boot are the same thing.
A cold boot is when the computer is off and you start it up with the power switch.
If your PC has a RESET button on the front panel, pushing that results in a cold boot.
Real men don't use AntiVirus; they just reformat