Quote from SlamDrag
1. All CPU's need a CPU cooler, which is why every CPU comes with a cooler. You can buy aftermarket CPU coolers if you want to overclock. Case fans come with your case. The only reason to get different case fans are if you want quieter fans or better performing fans, or if you want a specific color scheme (the default case fans are 99% of the time fine unless they are defective somehow, in which case you can generally get a replacement from the manufacturer.
2. Yes probably, but unless you're careful you could easily end up getting a CPU cooler or case fan that's worse than the defaults.
3. Yes, you would need to get a wifi card to be able to connect to your wifi.
Oh, so all CPU's already have a CPU cooler and all PC's have a case fan already, and the extra ones are optional, right? But I'm going to probably need an optical drive thing (for gaming as some games I'll probably use a disc for instead of download) and I might need a wifi card so I could connect to wifi (sorry that I forgot to put it in my main post before). So, because I don't know which parts are compatible and because I don't know which parts are good or not, may one of you please add a wifi card thing, an ethernet card thing (IF you need one of those too to use ethernet), an optical drive (that works with dvd's and cd's/game discs; I don't care about Blu-ray), and a sound card to this build?(only if the sound card is needed for the sound to work. I don't need it if it isn't needed, though)? Also, please try to not exceed the budget ($620) and being lower than it, when possible, is always better! Thanks for the help.