My computer won't pick up my graphics card, only integrated graphics. Help?

[Corvidae]

I recently bought a new computer specifically so I could play high end games; I'm not incredibly tech savvy and I'm sure you're all like me in the sense that when you get a new toy (ie, computer) you just want to play the crap out of it.
So, low and behold, I try and play one of my favourite games (Team Fortress 2) and the graphics are HORRENDOUS. I then find out that my computer is using integrated graphics- NOT the 100+ quid (UK currency haha) graphics card I bought.
I have literally exhausted EVERYTHING I can think of in order to get the thing to show up in my devices.
My motheboard is an ASRock Wolfdale 1333-GLAN/M and my graphics card is an ATI Radeon HD 4850 512MB.

Please help, it's driving me crazy not knowing how to use my graphics card; also, the thing is inserted correctly into my computer

[EDIT] Also, I'm using Vista 32 bit!

[BC_Programmer]

you need to disable the on-board graphics via your BIOS setup.

You also need to plug your monitor into the video card, rather then your on-board output.

[Broni]

You also need to plug your monitor into the video card, rather then your on-board output.

This may be the main issue () since most newer cards should disable on-board video automatically.

Also, driver installed?