I would look at maybe replacing the thermal paste on your cpu, and maybe relocating your SSD, it seems to be very very hot. ARe you using a stock cooler? I would suggest a complete strip down, clean and rebuild then maybe a better cpu cooler
A ) The thermal paste is drying up.
Given that you don't know what specification your build has, I'm going to assume it's a pre-build. So they may have cheap out on the thermal paste and now it is drying up and causing heat issues. To fix this, acquire thermal paste, rubbing alcohol, and coffee filter/high quality napkin/tissue (something you're ok with using once and throwing away as it won't be usable again after this). Take off the CPU cooler, dump a bit of alcohol on the filter/napkin/tissue and clean off the dried up thermal paste on the CPU and the heatsink. Reapply thermal paste and put the CPU cooler back on. Here's a nice video Linus made.
B ) The fan is dying.
Not much you can do about this except getting a new fan. Check your CPU cooler and see what fan size it's using and whether or not it's replaceable. The fan size there is is 80mm ,120mm , and 240mm. If the fan is replaceable, simply buy a new fan according to the size and replace it. A good recommendation for fan is Noctua. If it is not replaceable, you can ghetto hook on a new replacement fan or buy a new CPU cooler. Hyper 212 and Noctua NHD-15 are good recommendations.
