That sounds like a chipset driver rather than a CPU one. I see that Dell don't supply any Windows 2000 drivers for that particular model so obviously they don't support 2000 on it.
If you're lucky you may be able to find some generic 2000 drivers for your wireless network chipset. Google the appropriate chipset number and see what turns up.
The answer to your original question is that you probably can't get an XP driver to work on 2000. Why does it have to be 2000, not XP? Even XP is almost obsolete nowadays - Windows 2000 is long past its sell-by date.
When you say "wireless network chipset" what do you mean....like dell wifi card 1395?