How to fix pc and panel

I have some kind of problem with the panel and with the system, when I turn on the computer (system) and do not log in to the panel, everything works fine, nothing buzzes, as soon as I log in to the panel, the computer immediately starts to slow down, buzz, and the panel stops working in less than a minute, how to fix it?

Is that thermal throttling? did you build this computer yourself?

no, i use my old laptop