Exclusive Microsoft blames PC makers for underwhelming Windows 8 sales over Christmas, The Register has learned. The software giant accused manufacturers of not building enough attractive Win 8-powered touchscreen tablets.But the computer makers are fighting back: they claimed that if they’d followed Microsoft’s hardware requirements and ramped up production, they'd have ended up building a lot of high-end expensive slabs that consumers didn’t understand nor want.The Reg has learned Microsoft provided clear and specific guidance on the hardware it wanted inside any machine running Windows 8 so as to show off and utilise the operating system's