If I Paint My Walls Will That Cover Up The Cat Spray Smell?

No, some paints help like Kills, but none get rid of the smell completely. Try cleaning everything with a cleaner that has enzymes in it used for pet urine and then use Kills paint. That should take care of most of it on the walls. Remember the smell is in the floors too and probably on any surface the cat could reach. Use a black light to detect urine spots in rooms with the lights off.

Dude, no.  You need to just live with it or get a new cat.  If it is a fixed male cat and he is still spraying, hes going to spray for the next 15 years (if he's 4 or 5 years old).  Get used to cleaning all the time or get used to the smell.  Also, forget about any kind of social life because your friends will likely not stick around if it smells like urine all over your house.  This is exactly why I only get female cats.  Although the males are much more lovey!!!