Under $1000 your looking at a gtx 960m which is actually fine for light gaming such as cs go, tf2, minecraft, ext but when it comes to bf4 or gta v you will have to lower settings take a look at this chart I found
Yes that cyberpower case is uh something but it will definitely be better for rendering. Bestbuy lists it as a quad core but its actually a hexacore with 12 threads.
Eset has one of the best detection rates but I don't know how much of suite it is. They do have a package with a nice firewall or antispywear/phising you can get a trial here http://www.eset.com/us/download/home/ and if you cant afford it you can just redownload the trial every month :)
As far as I know Roms don't contain viruses which is why when you download them never do it in a .rar file as a "worm" could be in it as well and scan before opening it. I also recommend getting a better anti virus such as eset they have a trial that you can just keep getting until you buy it...