I have a old celron computer, just wasting my room space, I got an idea that, instead of wasting that hardware can i design a server through that system. It have 20 GB HDD and 256MB x2 512 RAM, running at a nice speed.

How can i proceed the work to use it as server, i had centos package already, then which are the software i require additionally, for which type of internet connection i want to consult ISP ?

I know it will not bring a professional service like xeon, but only need what it can provide ..