Hi, Lata and e_a_g_l_e_p_i . . .
The free software I use to download entire Youtube videos is DVDVideosoft. http://www.dvdvideosoft.com/
It can download either the full video in its highest resolution (sometimes 720p) as well as download just the audio - your choice. It's got beaucoup other things it can do, but those two are the only things I use it for.
Thanks for the heads up about being able to post software to help other members. Don't want to be considered a spammer!
Having said that, I've been using the software for about 3 years now with no problems. So much easier and better to edit the complete video than a screen capture!
They do update the software often, but I think that has more to do with Youtube changing or tweaking things. For a while it seemed like there was a new update every month (2 years ago) and you weren't able to download without updating. Again, I think that was more to do with Youtube changing stuff up than anything else.
To use the software, just fire it up and cut & paste the Youtube URL into the entry form (you can insert many video URLs into the form for a single download) and click *download*. That's it!
Proud VS user ver. 3, 4, 5, 7, 8, 10+, ProX2, and ProX4
Currently - VS ProX4 22.214.171.124
C3DPS ver 1.0.1