Laptop getting slower and slower

[Backstay]

Back when I got my laptop back in September 2015, it ran perfectly fine. It's a gaming laptop, so it's obviously supposed to run games well. It did run games well to begin with, but now it's gotten very slow. I feel like it begins heating up pretty fast, and the games I used to be able to run with no trouble, are not running very slow for me. An example would be Counter-Strike: Global Offensive, which I was able to play on highest settings with smooth 60 FPS. Now the highest I can get it is 50 on the absolute lowest settings possible through tweaking everything. And even then it keeps falling down to 20-30 regularly. But it's not just Counter-Strike - it's also games such as World of Warcraft, and basically anything. I even launched the old Call of Duty 2 yesterday and experienced consistent stuttering. That game is from 2005. It's horrible how bad this laptop is running things now. I don't know how the laptop got so bad. The soundcard is also close to being broken, I think, as I get crackle noises whenever sound plays while the computer is lagging. I don't know how to solve this, and I don't even know if it is possible to solve it, but I'll give some specs and just pray that someone is at least able to point out what's wrong. Yeah, I'll start with the specs, so let me know what else is needed to know. Maybe a system restore is the way to go? Unless it's hardware related and I need to have it repaired.

The laptop is an MSI GP62 2QE Leopard Pro.
CPU: Intel(R) Core(TM) i5-4210H @ 2.90Ghz (Quad Core)
GPU: Nvidia GTX 950M
RAM: 8GB

I know it's not perfect specs, but it ran things just fine when I got it. Now it's just a shadow of its former self.

Checklist:
- Disk Cleanup on both disks
- Ran AVG PC TuneUp to fix various things
- Disk defragmentation
- Virus scan
- Uninstalled unecessary programs
- Cleaned up the programs that start when the computer boots up
- Ran Malwarebytes

 

[BadActor]

Laptops suck in quite a bit of dust and lint, so I would try cleaning out the cooler. This sometimes requires taking it apart. Run Malwarebytes Malware cleaner and Adware cleaner. Make sure that under your Power Plan, that you are using High Performance. Check the performance tab in task manager and look for any unusually high CPU/memory/storage and network usage.

 

[Backstay]

Laptops suck in quite a bit of dust and lint, so I would try cleaning out the cooler. This sometimes requires taking it apart. Run Malwarebytes Malware cleaner and Adware cleaner. Make sure that under your Power Plan, that you are using High Performance. Check the performance tab in task manager and look for any unusually high CPU/memory/storage and network usage.

Yeah, I thought about the dust thing as well, but it didn't seem to be the case. I had some trouble picking the laptop apart and opening up the back, but at one point I could almost pick the entire back off, and there didn't seem to be any dust or anything. I've checked the power plan as well, and I always run High Performance. I've also tried restoring the power plan to its standard settings. Gonna try to run a game when it's done scanning, and have the task manager open on the other screen so I can see if there's anything going on there. I'll go get Malwarebytes as well.

 

[velo3100]

Have you replaced the thermal paste?