Ok. I just fixed it, here's how I fixed it.

This was a very strange solution, so I decided to turn off microphone access. (for voice) When I got back to GTA 5, The keys synced so well with the game. I just turned it back on to make sure it was that. And when I did, the game lagged, and the keys did not sync with the game. I was now sure that it was that and I quickly turned it off. I now can play the game with a little sacrifice of not allowing the microphone.

@jamesays, Darn, the Data (D:/) was the only one to handle the game.

@jamesays, I had no option but to install it on C:/ Did you read what I wrote?

@jamesays, Ever since I installed it on C:/ the issue started. Plus, I had 300+ car mods and it didn't lag on the D : \ drive. So it's not the amount of cars I have. ._.

@MurkyMamba, my GPU is Nvidia GeForce GTX 960 GPU. My Processor (the CPU, right?) Is 6th Generation Intel® Core™ i7-6700HQ Processor (2.60GHz 6MB), and the ram is 16 GB DDR4 2133Mhz. This is the correct info, right?

@MurkyMamba, Sorry if I seem a little unintelligent, but what is a hardware name?

@Kieran_S, Almost of those apply, I don't have malware, I didn't have graphics mods and it was still slow, and there are no unneeded scripts.

@Kieran_S, I'm using the primary HDD, (C:/) I've encountered this on the first time I installed it. Thing is that I can't remember exactly how I fixed it.

About 2 months ago, I was modding gta 5, and then the Data (D:/) is suddenly gone. So I used my Windows (C:/) Drive, and the performance is absolute trash. Like when I'm driving a car, I've stopped pressing the W key and it goes on for like 5 seconds more, this happens with a character or anything. And I also could exit with the windows key, but now I can only exit with Ctrl + Esc, and whatever quality the game is set to, the system gets set to that quality, please fix this.