You'll just have to try it; it may be too old. Normally, if the board has any vista or windows 7 drivers on it's webpage, then 8 might work. But I wouldn't spend any money on 8 unless you're prepared to change the board if needed.
Thanks. Somewhere I read that the MSI K8N will work with Vista but probably not with Windows 8. I was trying to verify that with you experts! While I built my own computer, I am a newbie. Will most replacement motherboards just fit right in place of the MSI if I follow your suggestion? Any suggestions on a replacement motherboard? (& CPU?) The MSI K8N was pretty quick and I didn't even try overclocking. But I'm not a gamer so I don't need lightening speed, but its nice when pages load quickly.
You'll need a firm budget for the cpu/board/ram. You might even find a great deal on craigslist if you live in the usa. Some combos with ram go for under $100; and some sellers will install if for free to sweeten the deal. The best deal I saw recently was an i3 540 with gigabyte board and 4 gb of ddr3 for $80. And windows 7 pro unopened for $50; same for windows 8 for folks who attended conferences or had systems provided by their employers. I live near austin tx, and the techies here are great.