Creating a PC screen from a TV???!!!!!!Possible?

Hey AD visitors...
I have a question. THis actually might not be the right place to ask but I dunno where to ask it...
I would like to take a tv screen and make it into a PC screen..Is that possible? Because I see ads in the advertisemnents that say "PC Input" does it mean that u could use it as a computer screen?
IF so
...would it be complicated to do?
...are there any disadvantages or advantages? (ex.disorted image or bad quality image)
...Would I still be able to watch tv on there???say cable?
THnx for any answers given

 

oh srry...i didnt mean to create two of the same threads...it hust wasnt showing up so i thought it wasnt created so i created another one...Im sorry afterdawn...any way to delete on eof them???