(redirected) Dell Inspiron 14z problem

Sorry if I am in the wrong place but my laptop has been bleeping 8 times on bootup but then seems to work ok, if it bleeps during use I swich off then on again and it is ok. I read something that suggested that it may be an lcd issue but the lcd seems fine, however the last time the bleeps happened I turned off my laptop and I now get the windows boot manager screen and the message 'Windows failed to start. A recent hardware or software change might be the cause.' I took it to PC world who said I need to buy windows 8 again, I googled the problem and I can buy a repair and reinstallation disk but I must have the windows sticker on the underside of my laptop to give me a code - I have no windows sticker though so I am stuck what to do -any help would b appreciated. p.s. I am not very techie, thanks