fyi, HP sells replacement OS CD's for $15 or so...I ended up paying $12 shipped directly from them, but i dont know if our corporate/educational status is the reason it was so low a price...
Dell used to replace them for free. Now I think they charge but you can easily haggle for a free copy if your a small/medium/large business/govt/ed business segments...
Dell Precision WS470 Xenon 3.0GB 1GB PC3200 80GB SATA HDD
but...control 5 servers, one switch rack with 300 ports protected by cisco router, 300 PC's, 75 notebooks over a wLAN ;)