I have a pc running Windows 10. I recently contracted a computer service to unload some software because I wanted to be sure all of the little left-behind do-dads were taken care of. I said OK to their anti-virus software (not thinking; I prefer another name.) Turns out they installed Bitlocker which wouldn't let me start in safe mode without a password that I don't have.
Numerous phone calls and a few hours later, the antivirus was removed, then the Bitlocker software. I had no anti-virus installed so I called the number I got from the internet. A while into the conversation I realized that I was talking to an Avast employee. Oops, wrong number, but we were already into the works so I looked paid more attention. This Avast employee took control of my computer and found lots of those little do-dads that the computer tech missed. I watched as we went into the registry and deleted dozens of keys. More "junk" was removed, a few restarts, over an hours work here. The total cost from Avast (including a year's worth of tech support) was 60% of the Computer service I had initially contracted.
Avast treated me very well and I'm pleased to recommend them to anyone.