Unless you have a live video feed so that you can see what someone is doing in your equipment in real time, you cannot be sure of who it is who’s in your equipment. There is also always the possibility that someone else has HIRED hackers to hack into your equipment. That could for example be the case if you are dealing with someone who has an antisocial personality disorder.
Also, my HDD is NOT the problem, no. (I should have mentioned that before.)
Things have been pretty quiet and normal since about 2 pm yesterday.