@BASE-CAMP
Given the date of your post, I would have expected someone to respond to it before this -- but since that has not happened, I will take a shot at it ...
I think that no one has responded sooner for two reasons.
First, you provided no details at all about this supposed hijacking -- when it happened, what you are seeing, what is no longer working, etc. Without details, no one can do anything.
Second, if you were truly hijacked then the only SAFE solution is a complete wipe and reset of the laptop -- meaning, you will lose everything in the process.
We need the model information and the details to the first issue in order to provide any advice.
I am a volunteer and I do not work for, nor represent, HP