My laptop is an old HP Pavilion dv6000 running 32-bit Windows 7 Professional that still works pretty good except I believe I am infected with a rootkit. It is very similar to the one in this thread:
I have basically the same symptoms - CPU fan runs constantly even though task manager shows everything is running smoothly, I have lost some admin rights, almost all of my services are stopped, etc. I ran Malwarebytes and it cleaned lots up and everything seemed fine until I rebooted the machine again which put me back to square one. I then decided I would run FRST.exe in safe mode, which afterwards I started thinking was a bad decision. Anyways, I have the FRST.txt and Addition.txt logs that I can post if needed.