Need a lot of help connecting to wireless

Hello,

Basically you will have to help me out a lot here as I'm pretty new to all of this.
Okay so I received a newly custom computer from my uncle about a year and a half ago.
I've been connecting to the internet through an ethernet adapter for the entire time with no problems what so ever. But then realised that he told me that he had installed wireless internet on to it, or something along those lines.

If I check the back of the computer I see that there is a kind of, signal type of thing thing, kind of like a tv ariel, but I have no idea hoiw to work it.
The only information I can find about the computer itself are two stickers, one that has MSI motherboard and another with GHI computers on it.

I'm currently running Windows XP Version 2002 Home Edition SP3 and am also currently connecting to a Zyxel P-320W Router.
And if I check device manager there is 1 'Other Device' that simply says Ethernet Controller.
I don't know if this has anything to do with it but it's quite possible.
If I go to properties -> Details on this device this is what I get.
Device Instance ID:
PCI\VEN_10EC&DEV_8185&SUBSYS_822513D1&REV_20\3&61AAA01&0&38

Hardware ID:
PCI\VEN_10EC&DEV_8185&SUBSYS_822513D1&REV_20
PCI\VEN_10EC&DEV_8185&SUBSYS_822513D1
PCI\VEN_10EC&DEV_8185&CC_020000
PCI\VEN_10EC&DEV_8185&CC_0200

Compatible ID's
PCI\VEN_10EC&DEV_8185&SUBSYS_822513D1&REV_20
PCI\VEN_10EC&DEV_8185
PCI\VEN_10EC&CC_020000
PCI\VEN_10EC&CC_0200
PCI\VEN_10EC
PCI\CC_020000
PCI\CC_0200

Enumerator:
PCI

Devmode Flags:
DN_HAS_PROBLEM
DN_DISABLEABLE
DN_NET_ENUMERATOR
DN_NT_DRIVER

Config Flags:
CONFIGFLAG_FAILEDINSTALL

Current Power State:
D3

Power Capabilities:
PDCAP_D0_SUPPORTED
PDCAP_D1_SUPPORTED
PDCAP_D2_SUPPORTED
PDCAP_D3_SUPPORTED
PDCAP_WAKE_FROM_D1_SUPPORTED
PDCAP_WAKE_FROM_D2_SUPPORTED
PDCAP_WAKE_FROM_D3_SUPPORTED

Power State Mappings:
S0->D0
S1->D1
S2->UNSPECIFIED
S3->UNSPECIFIED
S4->D3
S5->D3

Is there any other information I need to give?
And sorry for the very long question this has just been bugging me for a while now and I wanted it sorted.
All help is greatly appreciated, thanks.

Edit: Wow, JAck you just helped me so much, like I said I'm an idiot and realised the 'TV ariel thing' I was talking about before is a Wireless Lan Card already built in (Thanks to my uncle) to my computer, now I just need help actually using it...