Need help with installing graphic card.

[yupyupyup]

First of, I'm new to the forum, I'm tech-challenged, but quite enjoyed reading some discussions you guys have here.
Secondly, I have some questions regarding upgrading graphic card, which I haven't done before, and hope someone may give me advise/ walk-thru.
I just bought a new comp a couple days ago. It's an HP A6152N. Spec:
- Intel Q6600
- Vista Home Premium
- 400 G Sata (one)
- DVD RW (one)
- on-board Graphic
- 300 W PSU
Spec from vendor (CC):
http://www.circuitcity.com/ssm...lSpecification.do#tabs

I have an EVGA eGeForce 7600GT card I bought a couple months ago, and I wanna put it into this PC. I also have an 500W Antec SmartPower PSU. The spec on the card box states that the minimum requirement for the PSU is: 450W/ 18A@12V+. While the rating on my PSU is: 12V+ (1A-17A) for motherboard and peripherals, 12V+ (1A-19A) for the processor. I plan to add another int Sata HDD (250-320 Gb), maybe another IDE DVD R/W. My questions are:

1) With the retail comp and another 3 add-ons (card, HDD, DVD drive), is my Antec sufficient? Do you guys have any suggestion for any reliable, good PSU? I don't plan to overclock the chip or adding more stuff than those 3.
2) I've never access BIOS setting and stuff. May someone give me a detailed guide to install the card? (access BIOS, diable the on-board....)

Any help will be greatly appreciated!

 

[JPB]

Imo, that psu is plenty enough. The 7600GT dont use much power at all. As far as installing the card, When I would have integrated gpu, and was putting a card in. I would just insert the card, and it would auto disable the integration and detect new hardware. Then install drivers from there. I know some people will say this is a bad way of doing it. But it has always been flawless for me. No driver issues at all.