As someone not very confident with computer systems (or particularly knowledgable compared to most users) can i please ask for instructions as (a)to how download music from Youtube - presumably into the “MY Downloads” on windows 8? (Does this have to be in WAV format?)
(b) How to virtually eliminate vocals from a track?
I have looked through the FAQ and several other sections and either can’t find this info, or, it is worded beyond my recognition(!). I am familar with the Nero Smartstart for burning tracks to audio cds, it’s just the steps above that I can’t grasp on here. In short - an idiot requesting an idiot’s guide(!) - many thanks for any help forthcoming indeed. 
Sorry but you will need to search Google or Bing for how to download videos or audio from YouTube. Audacity does not do that, but it is the best solution because you will always get as good a quality video as the file is and for a long video this will be quicker than recording in real time.
If you download the video but only want the audio, download FFmpeg from http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#ffdown , then drag the downloaded video into Audacity. Audacity extracts the audio, then you can export the audio to any format you want.
If you want to export the audio to MP3, please see http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#lame .
If you want to record the YouTube audio directly into Audacity as it plays, please see: Tutorial - Recording Computer Playback on Windows - Audacity Manual . You can try the Windows WASAPI solution mentioned there.
Please make sure you have the copyright holder’s permission before downloading or recording from YouTube.
You don’t, unless you have the separate vocal tracks that went into the mix, or unless the vocals are panned dead centre in a stereo track. If anything else is panned centre, that gets removed too. If stereo reverb has been added, you’ll end up with a useless mess. Please see: http://manual.audacityteam.org/o/man/tutorial_vocal_removal_and_isolation.html .
If you are looking for Karaoke tracks, it may be better to buy them online or possibly find them on YouTube, rather than download the official song from YouTube then try and remove vocals from that.
Gale
Wow Gale! Many thanks for your speedy and informative response. Have to say that I am disappointed that audacity cannot download tracks for youtube directly but thanks again for the other material. Can you honestly recommend a program to extract youtube music at all - I have tried Ilivid which worked fine initially but it has so much other “sludge” attached to it that eventually I had to remove it and all its unnecessary baggage, which took some doing! Many thanks once again.
Just to be sure, do you understand the distinction I am making between download and record?
Audacity can record audio in real time from your web browser on your Windows 8 system using the Windows WASAPI host, even if your sound card can’t record computer playback. But it is very slightly lossy, and like “stereo mix” or “what U hear” that some sound cards offer, it will also capture any system sounds that occur while recording.
Yes iLivid is a browser hijacker/spyware.
Have you tried using a web browser extension to do what you want? This is usually the simplest method and usually fairly safe. There are many extensions that will download YouTube video. Once you have FFmpeg you can use Audacity to extract the audio from the video then export it to your chosen format.
A download manager that is able to sniff out the location of the video stream is probably the best general solution for downloading videos, as if it works with YouTube it will work with any Flash Player stream that the browser can play. Many browser extensions will only download from specific sites.
Gale