I used to have an Abit ZM6 once, a Intel i440ZX based mainboard. i440ZX systems where available in Slot-1 and Socket-370 (not FC-370 though, so may lack Pentium-III support). The Abit ZM6 was Socket-370, mostly for Celerons up to 533 MHz. (The P-II based ones that lacked SSE though)
The i440ZX was limited to 256 MB of SDRAM (PC100)
off the top of my head. There was also a cheaper i440ZX-66 varient which wouldn't do 100 MHz FSB in all cases without tweaking and alot of luck.
A current sub AU$1000 system (even sub AU$700) would outpeform your PC considerably..... We are talking 4x - 8x improvements in performance (possibly more in some tasks).
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As said above, just upgrade:
If you are a cheapskate (i440ZX implies you are) consider pairing the following components, I don't know your world locality but look up the total price for the following parts from a few of your local vendors.
CPU: Athlon64 3200+ (Socket 939)
MOBO: Foxconn 6150K8MA-8EKRS (most overlooked mobo out there)
http://www.foxconnchannel.com/products_motherboard_2.cfm?pName=6150K8MA-8EKRS
Leadtek Winfast Foxconn - All the same company.
RAM: 2 x 512 MB DDR-SDRAM (PC3200) (Kingmax, OCZ, Kingston, Corsair, etc)
VID: Either use the onboard GeForce 6150, which is more than acceptable to most... (likely much faster than what you have now, which is prob a TNT2m64 / Vanta based card. Or less, a Diamond Viper v550 comes to mind). Can always use the GeForce 6150 no strings attached, then decide if you need more 3D performance and upgrade to a much beefier PCIe x16 video card to suit your requirements if need be.
CASE: Antec TX640 (black) or TX635 (beige) (They have good cooling)
http://www.antec.com/us/productDetails.php?ProdID=61640
PSU: Antec SmartPower 350 or 400 watt PSU, for futureproofing.
HDD: 160 GB Samsung (7200rpm, 8 MB cache, SATA, NCQ) - They have a good price internationally atm, but also check out Seagate, Western Digital, and what other HDD maufacturers are offering.
Sound (hardware accelerated, unlike older onboard Realtek / Azalia audio) & a rather decent Yukon Marvell Gigabit LAN are both integrated on the mainboard, leaving the PCI slots free for other things. Installing a Creative Audigy 2 Value is a pretty simple sound system upgrade to the above though if audio / EAX support is a concern.
.... and anything else you may need. eg: TFT / CRT Monitor, DVD+/-RW, Windows XP Home/Pro Operating System, etc
If you are in ACT, Australia contact me (details on my website, see my signature far below), can hook you up with some much nicer gear.
If the Intel i440ZX is indeed limited to 256 MB (as I remember it being anyway) then it would be almost antique compared to the above specs and not even cost effective compared to the above*. Your time would be better invested earning the apx AU$1000 (or equiv) to arm yourself which such a huge PC upgrade.
* (Which is the stock system I recommend to people, seeing what they want to change on it tells me what the person is really after, the GeForce 6150 onboard is ample for business and most SOHO users)
I've upgraded many times since my trusty old Abit ZM6, going from such a system to the above, in one step, would show you how times have really changed, you'll also be x64 ready.