So I built my PC about a year ago and it has about 4 fans (maybe 3) in it. The problem is that these fans (when playing pretty much any game) vent a lot of heat and can sometimes get a bit loud. I know this is a good thing, but are there any other cooling solutions that would be relatively easy to install that would be quieter and reduce the amount of heat generated? I assume I am wanting liquid cooling, but I have no idea how that works or how to even go about installing/buying it. Any help would be awesome!

You can install basic liquid cooling kits for your CPU.

Installing any liquid cooling beyond that will be a bit more involved, I would google around for some guides if thats the way you want to go. This might also depend on the amount of space you have in your case. Liquid cooling is generally a more expensive option used when people want to get the most out of their system with overclocking. I'm not even sure if it's that much quieter than a good air cooled PC.

Air cooling is always a sufficient option unless your computer is set up in a sauna or something.

The best and cheapest solution would be to look into purchasing some better and quieter fans, stock case fans are generally pretty underwhelming.

Could you provide some pictures or details of your case? Ensuring you have a good airflow across your hottest components is important, generally your GPU produces the most heat. With better airflow I guess less heat will actually be produced because it will dissipate faster and the components won't rise to as high temperatures.

Best suggestion is what you call a "closed loop" water solution and their actually very effective, most people use those now isntead of the insane banana water cooling you see on youtube lol....... Here are a couple examples, you just simply install them like you would with a regular heatsink for your CPU pretty much and thats it, no mass tubing to mess around with, no massive water resovrior/radiator you have to deal with outside the case or anything.

COOLER Master Seidon 240

CORSAIR Hydro Series H80i water cooler

Thermaltake CLW0217 Water 2.0

Realistically the noisiest fan in a modern PC is going to be the video card if it's running a stock cooling solution. Replacing the fans on those can be pretty simple however you will need to keep in mind that doing so will void most vendor warranties (there are a few who are fine with it).

CPU stuff is simple enough although realistically if you are only running stock clocks the stock cooler shouldn't get to loud. If it does swap it out for something with some large low rpm fans or a close liquid solution like the H80i.

Like others have said, first you need to identify where the majority of the noise is coming from. The fans in my case for example are great, getting in lots of air but staying quiet and if I'm playing a demanding game, the only thing I can hear is my GPU.

I always hear a lot of good things from Noctua fans. They're supposed to be high end air cooling, but they also cost like high end air cooling. lol

yes Noctua fans are very good, and quiet.

"Best" seems to be liquid nitrogen:

LOL.. ok no need to get ridiculous here :D

The premade watercooling kits are usually not that much better than what you can achieve with air .

Regarding the heat, Your computer generates the heat. your cooling solution grabs that heat and throws it out the case and into your room, if you buy a more efficient solution, your components will be better cooled, but that means there will be more heat going out the computer and into your room, you cant make it magically disappear, without introducing coolant constantly, for example liquid nitrogen, or a water cooling solution with a radiator outside your room. or a peltier element (thermoelectric cooling).

of course these advanced solutions wont make the heat magically disappear either, it just makes it go somewhere else that isn't your room.

To combat the noise, identify what components are making it, most likely the cpu or gpu,
Dump a huge cooler on it, and perhaps replace your case fans for some that are more efficient instead of loud ( if they are loud ).