Got a desktop of one of the market

[AspoX]

I purchased a desktop of the local market where i am currently staying w/grandparents and i am gonna be adding this to my homelab and kinda stuck on what to turn this into server wise if someone could give me a idea plz i already have a win server and a virtual machine server using citrix xenserver
Dell inspiron 560
4gig ddr3 320 7.2k but gonna put a 750g 7.2k in there i
ntel cerlon 540 dual core 2.2