Ok. That gives a starting point.
I would recommend as much PC as you can afford. As fast a processor, as much ram and hard drive space as you can swing. And a CD burner.
If the Dell has on board sound (i.e. on the mobo vice a separate card), make sure you can disable it.
I would personally recommend an MAudio 2496 Audiophile sound card ($149) and a Behringer UB1202 mixer ($79 at MF).
How do you plan on doing drums? If you want to loop or use virtual instruments, I would recommend Cakewalk's Sonar 3
Studio ($259 at MF)or Steinberg's Cubase, which I have no experience with but it is the other big home studio seller. With these two programs, you can use drum loops or midi virtual instruments.
If you are going to go some other route for drums (i.e midi out to an external drum machine or something), then you can get away with a cheaper program, say PG Music's Power Tracks Pro Audio ($49).
You also need to have a decent mic (even a generic SM58 will do), and you'll need something other than standard computer speakers to monitor on if you want to turn out decent mixes. Something like the MAudio BX5
monitors ($299 at MF) would work well. Depending on your budget, you can wait on the monitors, but you will want them eventually.
Hope this helps.