OK - First off, shove the K7 CPU out the window, there NOT good for this sort of thing, (I hate to say it) but pentiums are better
Cooling - as long as its quietish all you need is a single baffle infront of the PC in your studio room to where your recording for that to matter (music stands and acoustic matting = great cheap sound baffles).
Although I would also recommend mAudio - that card will only allow one input at a time. I would recommend the Delta 44 as that allows 4 ins and 4 outs which obviously can be much more versatile, if he can afford it I would choose the Delta 1010 which allows 10 ins and 10 outs. Don't buy from Kustom, its a rip ...
http://www.soundslive.co.uk/moreinfo.asp?ID=114 would be great, and you can take the aux outs on your desk straight onto that. For a rock recording eg you could do everything but the drums in one go - then use all 10 channels for the drums
Whereas with only 4 inputs your going to be mixing down for the drums anyways (im taking a guess at what he wants it for, but still).
Just read your previous post ...
Why are you using a mixer if your only inputting one thing at a time? decent cards allow for high gain ajustments so all the desk does is reduce quality and increase complexity.
I would then get a good mastering grade soundcard ...
http://www.soundslive.co.uk/moreinfo.asp?ID=3218