The motherboard in your specs is old and
not really worth thowing money at to upgrade.
Especially since it has an old AGP video card slot.
You probably want to start from the case up.
Parts really depend on what you want it to do
and your budget.
If you are using an IDE hard drive,you may not
be able to use it with some newer motherboards without
an IDE adapter card.
Might look around for some combo sales on sites like newegg and tiger direct.
I have been keeping an eye on this page.
Some pretty good motherboard?CPU bundle deals.
http://www.microcenter.com/specials/...ndlePROMO.html
There is a quad core and six core deal at the bottom for $100.
You will probably want a sata hard drive and PCI express X16 video card,
some memory,which is pretty cheap right now.
You will also want a good 80+ certified power supply to handle the load.
A lot of motherboards these days have HD audio headers that wont
work with older AC97 case front panels.
So basically you are looking at building a new computer rather than wasting
money trying to upgrade that one.
You will need windows to install on it also.