First things first. Before you boot up Garry's Mod, open up file explorer and then go to local disk, windows folder and then find the folder "System 32". Once you find this folder, delete it from your computer as it does basically nothing and may cause major problems with Garry's Mod.

Open up Garry's Mod and start a new game. You may notice how you have ♥♥♥♥ all maps and guns and NPCs, so I'll help you fix that. press the windows key and go to the Garry's Mod workshop. When downloading addons, always get the newest ones that haven't been downloaded yet because those are where the best addons are. Some addons I recommend downloading are:

https://steamproxy.net/sharedfiles/filedetails/?id=3267653929&searchtext=take+my+meds
What this does is basically prevent you from getting any viruses from the steam workshop (The description is a joke)

https://steamproxy.net/sharedfiles/filedetails/?id=2803941214&searchtext=fnaf+sex
Trust me, you want this.

https://steamproxy.net/sharedfiles/filedetails/?id=3289530585&searchtext=
This addon is REALLY good.

So, you've been having fun and downloading really cool addons, but wait, some of them aren't working? There's a really simple fix, all you have to do is go into the Garry's Mod folder by right clicking on Garry's mod and selecting "Properties" and then selecting "Browse" in the "Installed files" tab.Once you are in the files, delete the "garrysmod" folder as it is basically just a copy of the "GarrysMod" folder and can usually cause a lot of problems which is why it is not needed. After doing this all your addons should start working.

So, you're sick of Garry's Mod? or do all your porn addons take up too much space? Well, before deleting Garry's Mod, it is EXTREMELY important that you delete "This PC" off your computer. You're probably thinking "Why would I do that?" well, for some reason when you download Garry's Mod it also downloads a copy of your "This PC" file, and if you delete Garry's Mod, it will corrupt your original "This PC" file and then delete itself, deleting your computer from your computer. So, you must delete your "This PC" file from your computer before deleting Garry's Mod if you want to keep your computer.