Good PC but bad FPS after several months of use?

Bought my son a relatively good PC a few months ago, but he has obviously noticed a strange problem that seems to have occurred only two days ago. (He takes over as he can explain better): First my Specs: RTX 2060 Super, Amd Ryzen 5 3600 X. I have the PC for about 2-3 months and at the beginning ran all the games I played great. (Overwatch, Csgo, Fortnite, Rainbow Six) Two days ago I started with Fortnite and got an Errormessage. Application Hang Detected. Do not know if that has something to do with it. Other games such as Overwatch run suddenly only on very little fps, previously had at least 200 to 300 with the same settings. All other games I have also tested and there it was similar. Any proposed solutions? Have tried so far: update video card driver, in the background running clip program uninstalled, temperature of CPU and GPU measured (was both good), virus check performed.

There are several causes for your problem! Amongst other things:

Virus on your PC (viruses are very powerful)
Graphics card / CPU / … Driver Not current
Defect of one of the components
Installation of a program that eats a lot of power. (Can you check the Task Manager: CTRL + ALT + DEL)

Solution: Just put the PC back on, then it works normal white to 99% back to normal.

For further questions, please do not hesitate to contact me!

Have you already checked the standard way things like all unnecessary from the Task Manager rausschmeisen and so?

Such problems rarely occur on their own. Did you download or modify anything?

If you want to save yourself the troubleshooting you can just put it on again.

How much RAM do you have?

Look in the Taskmanager if something pulls the achievement. Otherwise I would recommend the virus program to uninstall, if available.

If you show usage and temperatures in the game, for example with MSI Afterburner, what do you get for CPU and GPU values?