what do these do?
 

what connects to a the Line in Connector , surround connector, center/LFE connector, and serial connector??
I dont have anything connected to them and i was wondering what i was missing out on?
The are on the Back of the computer.

sounds like either a mobo or a sound card?
Where are you reading these names, eg what hardware are they written on?

Phantom Ports
 

...sounds like speaker and joy stick outlet ports... do a google search of them...

serial: used to be common for printers, not many computers use them now, unless used for some sort on analysis device.
center LFE: is an audio line, for Low Frequency Effects
surround: is a connector for surround sound speakers, thus containing a line of sound which can be split into 5 or more points.
line in: usually an audio or mic line for audio input.