I have a used compacq 530 but do not know what is missing because i cannot get it to hook up to the internet

Possibly if you gave more information .....does it have a network card installed, is the network card "enabled" in the hardware settings, does the network card have correct drivers ? ( no yellow question mark beside it ) Do you have an internet provider and account ? Is your internet high speed or dialup, if it is dialup, do you have a modem installed - with correct drivers ? Is it working - do a modem query to see if it responds ?
If using a network card and cable or DSL internet, is the cable connected from the PC to the cable or dsl modem ? Is the cable or dsl modem plugged in and the power and wan light on ? With the little bit of information you have given, it is not really possible to give an exact answer to what the problem is.