Okay, now I just feel silly. Paranoid and silly. But this problem really bugs me.

The Chkdsk found no bad sectors. But it did fix some other problems.

Now I am starting to blame my power supply. Or maybe some sort of damage to the mainboard.

USB devices now sometimes stop working. Almost as if they just don’t get power anymore, and has to be re-connected. I almost panicked when Windows reported that it could not recognise my full 2Tb drive, because it could have been damaged. however, my laptop found it just fine.

Later when I tried connecting it to the stationary again, it worked as normal.

The same evening, I got that error on a usb pen, as well. Then my keyboard had to be re-connected every restart. But that has fixed itself. Atm. everything seems to be working as normal. Until it randomly looses sound, all browser plugins crashes constantly, and refuses to start anything at all.