your gonna need the Socket A cpu, Semprons are fine and a little cheaper, but if you got the extra cash, then go XP2500+ barton, more L2 cacheCampbell685 said:
Asus and gigabyte mobo socket A NF2 is good, why do you need 5 pci slots, that may not be available, new boards have on board LAN and sound so you wont need your current ones, your gfx card may be ok it just depends on the slot voltage as was mentioned would need more info on card to know.
You will need PC3200 DDR400 ram 512 recommended
You should run your new system on Win2000pro or XP
Also need what case and psu you have currently, you should have a 400 watt min/ quality ATX psu, ie, Antec, Coolmax, Sparle, Enlight, your case should have a min of 2 80mm fans, more would be better to keep new cpu cool.
I checked your mobo and it says it has agp 4x so you should be able to use your gfx card if you like. your current ram will not work though only PC100/133