Computer Overheating Issue

Unless there was too little thermal paste applied when the CPU cooler was put on or the thermal paste was shit stuff there's no real way that could be it. The paste can last for years, and by the time it does need to be replaced the CPU itself will probably be swapped out anyways.

It could be dust related, unplug the PC and clean it out, though unless there is a mass of dust clogging everything possible there's no way it could be that either. CPU's are designed to have maximum temps of just over 100 C, so if it was overheating then it wouldn't be at just under 80 C, my old i5 4670k ran at just under 80 when under load just using a stock cooler.

It could be your power supply, unless you're getting thermal related shutdown codes. PSU's have a chance to randomly turn off when they are dying out or have an issue with them, to prevent the system from being damaged.

There's also other possibilities such as RAM being damaged somehow or your CPU itself dying (which shouldn't be the case). I think you should just clear all the dust out and if it doesn't fix it then just take it to the PC shop, unless you have the time to test everything out.

Yeah I've had power supply issues in the past... my last one blew out and was fried. Maybe it isn't powerful enough?

Underclocking your cpu will lower the temps.

You also need a liquid cooling unit. Unless you live in the arctic no simple fan will cool a gaming intended cpu. This isn't the 1990s, go buy a liquid cooler for 40 dollars.

If it was working fine until the past few months then it's obviously powerful enough, if it wasn't then it would've been shutting off from the day you got it. Do you know what brand the PSU is? Or did you buy the PC as a pre-built?

Try to clean the insides and if it still doesn't work get some new cooling

Forgot what company it is, but it's a 750i.

76 is a perfectly fine for a CPU. Anything under 80 is very good and anything under 90 is acceptable.

Must be a Corsair RM750i or a HX750i, which either are good since Corsair is one of the best PSU manufacturers on the market. Could have a defective one that only just became defective recently, or it could be a different component. Hard to tell just based off of text, just take it to the PC shop and see if they can sort it for you.

Its in Celsius not Fahrenheit

Yes, I know.

Never would've known 168F is normal for a CPU let alone 194F

Small 120mm fans won't make a difference, either buy a new PC case, CPU cooler or liquid coolers.

Liquid cooling is the best chance I'd say