Papa-T :
I've built a few PC's but I'm completely new to servers. A friend of mine told me that I could turn my old Dell inspiron 660 into a server but I have no idea how to go about doing that.
Does anyone know of any guides on this sort of thing?
Assuming you want a home media sharing and file storage solution, my recommendation would be to use a NAS OS like FreeNAS.
http://www.freenas.org/for-home/
http://www.freenas.org/about/videos/
Windows has network file sharing, although I find it much less versatile than using a NAS. If you prefer to stick with Windows, there are plenty of guides on how to use this feature.
Windows 8 file sharing