hum thats going to be hard, for 400 i could do it
get a duron
a7n8x-x (dont wanna get a cheap mobo trust me)
some normal graphics card geforce 4 mx200 anyone?
256mb ddr ram, pc2100 is enough
a nice power supply (dont get a cheap one, trust me again)
seagate 160gb for like $50 after rebate (yes i have 3 of them if you dont believe me, and yes at that price)
cd rom drive
floppy *meh*
cpu heatshink
sound card is intergrated into that mobo.
just some suggestions ^_^