For your second question, you may have to increase the samples and you may have to use clamping… These settings will depend on your scene setup…
For your final question, you have to jump into edit mode, select the portion of your mesh you want to detach and press P and choose Selection to detach that particular selected portion for your mesh…
Oh… sorry man… I saw your scene in your first post and the texturing looks good… and so i thought that you already knew about UV mapping… Cycles by default uses UV coordinates for mapping the textures… You may have to either UV unwrap your mesh (in this case your tv screen) or you can tweak the material by adding a texture coordinate node. Take the Generated output from the Texture coordinate node and connect it to the purple dot in your image texture node and you will be good to go…
Well, you might know this already, but since I cannot see this from your screenshots I would always suggest using a higher amount of samples (1024 - 2048) I would also change the size of your image as it is fairly large and would probably take forever to render.
Further, you can also turn on “No Caustics” and use clamping. For more information, you might want to look here: http://www.blenderguru.com/articles/7-ways-get-rid-fireflies/ Good luck!