Brutally slow after update?

I installed Windows 10 on my laptop yesterday via a USB stick. However, the problem is that it has slowed down a lot and I never had such problems with WIN 7. What can I do? Opening apps takes years… In addition, I think some apps are not installed correctly, because if I want to open Office, for example, it closes directly. Do you have any tips?

What does the Task Manager say? It should show you how much the CPU is currently busy and how high the current clock frequency is.

So 4% usage, 1.69 GHz the speed, 93 processes, 1261 threads, 45545 handles, and the graph is very low

And what about RAM? Does the CPU usage increase when opening apps?

Open the Windows settings and then click on System / Network operation and Energy saving / Additional energy settings. Set the setting there to maximum performance.

Yes it goes up when I open an app, but it closes again after a few seconds (the app)

Maybe there's an indication of the error in the Windows Event Viewer.

Open the times and then look under "Windows protocol / application" and "Windows protocol / system" to see if there were any errors at the time you started the app.

I don't know what you did. But maybe you will tell us yet! Did you upgrade from Windows 7 to Windows 10 and keep all programs and settings that you had with Windows 7? Or have you installed Windows fresh on the used laptop and now only Windows 10 is on it?