I just looked on Xandros site, didn't see a complete o/s that runs from one cd. I generally free up some disk space and then have xandros install as a dual boot system. never had any problems since it makes up the requisite partitions and keeps clear of your Windows o/s, as do most LInux systems I've tried.
The big question is what do you want to run on Linux. It is always a little disappointing with Linux because you no longer have the zillions of applications out there than run on Windows.
This link was on the Xandros site:
http://www.pcworld.com/news/article/...062005x,00.asp