Computer issues

I'm using pastebin for something other than code, I'm such a rebel
So over the past half year, I've been getting tons of issues with my laptop.
For those of you wondering, my laptop is the Acer Aspire 5750 from 2012. It has a dual core Intel i5 2410M / 2.3 GHz CPU, 6 GB of RAM, yadda yadda yadda.
1) About 4 months ago, I noticed that it shut off without me doing anything. After about 1 month or so, it started happening more frequently. I researched it and found out that it was overheating. At the time I'm writing this, my laptop has gotten to the point where it overheats at least 2 times a day, depending on what games I play (it hates Walls and Mega Walls)
2) Then, in December, I noticed my mouse was acting weird. The sensitivity of my mouse kept changing every 5 seconds or so. I could move my mouse at the same speed, then suddenly it would stop for 1 second and then go wild, like if I suddenly set my sensitivity to Hyperspeed or something. This makes completely unable to PvP or play any games based on accuracy, like Paintball or Quake, two games I enjoy playing very much. It's hard to describe tbh, so you'd have to experience it yourself to see why playing with this is impossible. And no, it's not a problem with my mouse, I get the same problem with my trackpad.
3) Another very recent problem is that I can't use my mic. About a month ago, my analog headset cable broke, so I had to switch over to USB (which is better, I get to use the surround sound feature of my headset and a sound mixer). However, my headset does not have access to my sound card or something. My computer detects that my headset is plugged in, but an error always appears. That is why I can't talk on Skype, Teamspeak, record or any other things that involves using my mic.
4) Programs also keep crashing (not responding) all the time. This is an older issuse, but it's still annoying af. For example, I like to make textures and things like that. I use Paint.NET for that, so this is a program I need quite often. The problem is, though, that it takes 2 minutes to start up because it stops responding every time I start it. Minecraft also stops responding every time I switch resource packs. Firefox crashes every so often. It's just a mess.
5) My laptop is very slow, just in general. It takes ages to boot up, which is part of why the overheating problem is such a big deal. I think this one speaks for itself.
6) This problem has been going on since 2013 at least, and that is my rubbish FPS in Minecraft. Nuff said, I get 20-50 FPS playing most games, 60 FPS playing Quake. Yeaa, it's bad.

I will still be on the forums and hopefully also ingame from time to time, but I won't be playing that much.
Olgaby has also helped me find parts for a new computer, so I will try and start building it asap.
-Ondrikus