Software is an extremely important aspect for a computer, and without the correct software a computer wouldn't even work. However, since this is a game-oriented website, I'm only going to introduce software and websites that can help you get games.
Humble bundle is a very nice website because if you are subscribed you get a list of free games every month as well as a 10% discount. It not only gives you games, but it also regularly gives bundles of a large variety of programs. It can be digital books, coding programs, online courses, game assets, among other things. I actually was able to buy 1200 dollars worth of online courses for a measly 25 dollars.
Steam is the goliath of the gaming world, with hundreds of millions of people having Steam installed on their computer. It allows you to buy games and software, find friends to play with, organize all your installed games into an easy to find group. Steam also gives large sales pretty frequently that allows you to save a lot of money.
Lag is the nemesis of every person who plays games, it makes it almost impossible to play because it looks like everything is standing still even though it's actually moving in real time. ExitLag is an application that when subscribed allows you remedy this issue. It provides a faster way of connecting to game servers that are farther away and reduces your lag. I tried it out when I was playing a game based in Russia and although the lag was somewhat there, it definitely helped because I could actually play the game.