Reading the installation notes for Windows 8 by Sony,

https://dbiz.sel.sony.com/secure/public-irsp-content/windows8.html it looks likely that even if you follow their instructions to the letter, unless your computer is one of the three models that they support, you will be on your own if you install Windows 8. To download the software from Sony that is a pre-requisite to installing Windows 8 is a 2.5 Gigabyte download. Add that to the download of about the same for Windows 8, and that will cost me £25 at £5 a gig on BT. Order the disk from Sony at £20, plus the same from Microsoft, + the £14.50 for the upgrade, and that comes to nearly £60. Even then you are not certain to have a working system, and the odds are that some of your programs will not work or will have lost data. Of course, you can always pay Sony £125 to do it for you. Plus the upgrade cost.

I don't plan to risk killing a £900 Viao investment by installing an at best clunky OS on it. Mine is an E17, and its touchpad is not usable in Win 7, so its not likely to be of any use in Win 8.

Forget about Windows 8 until you can buy a new computer with it already installed.