if i bye a new motherboard ,hard drive and operators system for a old pc from 2002?

[Bradley W]

I bought a computer today from 2002 if i bye a hard drive a motherboard and almost new operators system i just want a good computer i can play world of war-craft on and have music and do all the regular stuff on the net and not spend much money ??if i bye the 3 things listed above can i use the guts from the old pc(i mean wires and plugs lol)(sorry im computer illiterate