Windows costs the OEM much less, it's almost free when you add in the money they get from bundling software like antivirus trials etc.which they won't get from

Windows costs the OEM much less, it's almost free when you add in the money they get from bundling software like antivirus trials etc.which they won't get from installing Linux or selling without an OS. Also their support staff are trained to handle Windows. Adding Linux to the mix will increase costs.