Quick upgrade Question

[James_Stark]

Eventually I would like to build a new computer but for now I'd like to know if this quick upgrade would be worth it. MY current PC is:
Processor: Intel Celeron D 3.20 GHz
Ram: 1022 Mb
Graphics Card: Nividia GeForce 7300 GT with 512 Mb
Directx 9
Hard Drive: 31 Gb

I know the Hard Drive is extremely small and that's the part I'm looking to upgrade. Basically all I'm looking to do is run Team Fortress 2 well, I'm not looking to max all the settings but I'd like to play it on more than low. I checked my PC on systemrequirements.com and it passed just barely missing their recommended level. Will the hard drive upgrade help the problem or is there more to it? (Sidenote: I'm a complete PC newb and just starting to learn....and be overwhelmed) The Hard Drive I'm considering is the Western Digital Caviar Blue. So I guess the second part of the question would be is this hard drive easily compatible or are there things I should look out for?

[flanzig1]

The limiting factor is your video card. Your system sounds like a prebuilt like HP/Dell/etc. If so the PSU probably wouldn't be able to power a more powerfull video card.
Depending on how full your original HD is, adding a second drive for programs and storage could help some.

[Nikon]

as far as a hard drive goes, make sure (if the new HDD is sata) that you have an open sata port, or if it is IDE, an open IDE port. same goes for power, open sata power or 4pin molex.

other than that, hard drive just plug in and work. (usually)