I don't know if this is normal practice in the UK but I was helping a friend to buy a laptop and went into a large PC World store.
Well apart from the fact that 90% of the laptops on display were largish 15.6 inch screen ones everything was bolted down tight to the display so it was impossible to feel the weight of these.
Now I travel a lot and especially if you use planes size and weight is paramount -- a decent 14 inch screen (which can be plugged into a large monitor at home) is actually far more useful than those older 15.6 and 17 inch monsters.
I did see 3 smaller 14 inch screen "Ultrabook" types -- but just trying to hold them started all sorts of alarm bells and whistles in the store -- and also it was almost impossible to turn them around to see what type of connections they had (for example mini / standard HDMI or how many USB3 ports) or where the connections were --on the side or at the back etc. These sorts of things are important when choosing a laptop.
Finally all 3 of the ultrabook models WERE OUT OF STOCK !!!!! no notice on the display so a whole afternoon wasted -- A total text book example of HOW NOT TO SELL A product.
We then went over to an APPLE store -- no problem whatsoever --play with the devices as much as you want -- well my friend then bought an "Air book" which he's as pleased as punch with even though he paid nearly 850 GBP for it which was a lot more than he intended to. Running Parallels he can get windows to work as a VM as well.
If PC stores are selling (or NOT SELLING) stuff like PC world (only one of the largest physical computer retail stores in the UK) then you can't blame windows for the drop in PC sales.
Apart from making you feel like a criminal as soon as you walk into the store, and giving you about as much access to the product as the CIA would have given the old KGB back in cold war days to their latest gadgets not having STOCK when customers have the money in their pocket and want to buy is totally and utterly STUPID.
(Believe it or not -- it might cost a little more but for shopping in the UK try John Lewis -- even for computers !! -- and if the item has just gone out of stock they will offer you the display model at a discount too). I don't know if John Lewis stores are a different type of enterprise but the whole shopping experience is "on a different planet" compared with PC world - a much more pleasurable experience all round -- and coming from a person who hates shopping even for Beer and Milk that's praise indeed.
So it's not all Ms's or Windows 8's fault that sales of PC's are significantly down -- having outlets like PC world around just puts the boot in as far as I can see -- hideous atmosphere, nothing in stock, can't decently inspect goods, staff can't speak English decently and don't know anything about their products other than pushing "Extended warranties" or extra "A/V software" that you don't need or want.