from buying something just because an assistant got the information twisted round his neck.
If Windows XP is unstable it's because there's something wrong with the software/hardware setup, and it can almost always be resolved. I certainly wouldn't dream of buying a new machine with any other operating system on it, and you'll be hard pressed to find one. Manufacturers install WinXP on all new machines for one simple reason - it's better, and more stable than any other operating system on the consumer market.
Why you should say "needless to say we never purchased from their." beats me, and I wonder where you did purchase from? Wherever it was, I bet the machine had Windows XP installed.