Start in safe mode, then download/run Malwarebytes, CCleaner (clean comp and then registry fix), there’ll help. Open the startup folder in the start menu, delete all these shortcuts. Get Autoruns, that’ll show you a bunch of auto running programs you can stop.
Check installed programs in control panel, Google search stuff you don’t recognize, uninstall some stuff.
Been there, done that. Malwarebytes did not find any malware. CCleaner I run like every other day. Defrag disk many times. Clean Registry errors every other day. Tried stopping certain services. Nothing helped.
The slowdown issue was obviously related to driver for the battery. As soon as that driver was disabled, it was like letting a cooped up horse let out of the barn. Computer lag reduced 5 to 10 times!