Getting an XP CD from Microsoft?

[Mr Joshua]

This might be a stupid question but is it possible to buy a windows CD from Microsoft if you got a pre-installed system?

I can specifically remember reading a magazine letter about this years ago and I'm sure it said if you have your key they'll ship a disk to you.
I think my copy is the retail version (there's no OEM marking around the product key) so is this still possible?

 

[Mr Joshua]

Cheers for the responses. Theres an official looking MS sticker on the base but no mention of OEM, I'll contact them and see if they can help.