Dont forget that MS also throws dell and other OEMS monies that they wont be getting from linux vendors.
Umm there is no way MS takes a net negative on the operating system sold with a Dell. Dell pays them for windows not the other way around.
They don't take a net negative. The idea, is that Microsoft charges Dell a reduced rate (actually, I think it is a constant price no matter how many desktops Dell actually charges; the joys of volume licensing). Then other third-party vendors pay Dell to include miscellaneous utilities or demos on the computer. So, Dell is able to turn a net profit on Windows because the price they are paid per system by the third parties is more than the the price per system paid to Microsoft.