i proudly own a sony bravia and a sony ps3. my parents have sony tower speakers and a sony receiver. a relative also proudly owns a sony tv.
are there issue with sony products? sometimes, however there can be issues with any product. finding a+++ customer service is rather rare nowdays so while definitely sonys fault for not raising the bar it isnt like they are lagging behind the pack either.
now... i wouldnt buy branded desktop since building your own is so much better and i wouldnt buy a sony vaio laptop but thats for different reasons (mostly because i find the asus ones to be better in my opinion and they come with less junkware on them). keep in mind that this is only my personal buying preferences on the matter and not a go-by.
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in the case of laptops or computers it is quite commonplace to be given the runaround and not just by the manufacturers but also places which repair them as well.
the main trouble is that users really are not all that familliar with the device they are using so are completely at the mercy of whom they contact on the phone. in essence that is the reason why forums such as this are so popular. here on toms we love spreading knowledge around so that people arent taken advantage of by big business and so that they can save money and fix simple issues themselves.
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as for your problem... your hard drive could definitely be going on you however without running tests or hearing more to the story its hard to say for sure.
you already have a windows license (your computer came with one) and since you will only be changing the hard drive its not going to be an issue. there is no need to buy windows again.
if your laptop did not come with a backup disk or windows 7 disk or if sony refuses to give you one without cash in hand then dont fret there is an option. you can download the windows iso file (disk image) from microsoft legally! you can then burn it to a dvd or use microsofts tool to put it on a flash drive and you can use this to reinstall windows. your product key will be on a sticker on the bottom of your laptop or in the case of desktops on the side (or sometimes on the inside of the panel).
you can purchase a new hard drive for relatively cheap and normally installing one is not that hard provided that your laptop has a hatch on the bottom (does it? or provide a photo of the bottom of your laptop please in high res). if your laptop doesnt have a quick hatch for changing things like ram and hard drives then it can be quite a bit more trouble and you might not want to do it. if however you have a desktop computer then its very easy to do yourself.
once you have a new drive installed you would just use the windows disk you created and your product key to reinstall windows (the same version that came on your computer and the same version listed on your sticker).
once installed you would just need the drivers/software installed and that can be found here
sony drivers page