What is needed to setup a server at home, so ...

A pc case, preferably gutted of all but the bare bones systems. Examples are the power supply, the mother board (if it's a tower style server of an old pc) and it would be an excellent idea to take out the memory in the older pc.

buy a SATA internal card.

buy as many sata internal drives as you need

hook them up with thier power cables and connect them to your internal card.

replace your computer's old memory with no less than a gig of ram. the more ram the better in a server.

make sure you have a networking device, ethernet card, wi-fi card, etc.

then if you don't wish to use it for any other perpouse, you may not even have to use windows on it, if networked properly, the network will see it as a remote dive on the network.

Sure.. a fixed IP and server OS would be the absolute minimum required. The key to serving, is REDUNDANCY. This ensures AVAILABILITY of your [website in this case]. You'll notice for example, that a "free standing" -- i.e. not rack mounted -- server [tower] will have redundant power supplies (oftentimes hot swappable).. hardware RAID controller[s].. etc. (note: rack mount servers have all that redundant stuff too) So anyway, you'll notice that your garden variety "desktop" PC [architecture] lacks such redundancy. Same with your I-net connection. If it's not multi-homed -- i.e. redundant -- then loss of connectivity through your [single] ISP, will bring your site down. The good news is software. Gnu/Linux, 'BSD, -- even OpenSolaris -- etc. are ideal server operating systems; especially for stand alone home based servers, as they feature highly efficient utilization of system resources, and are available free of charge....