@Anthony_Barat Here's a good resource: https://decentsecurity.com If her data is backed up, I'd consider rebuilding her computer and restoring the data--not the apps. If she's on Windows, Defender is pretty good. I also like Malware Bytes as a second pair of eyes. I wouldn't bother with McAfee, Symantec, or Kaspersky.
@scottlink Yeah, I run Defender and MalwareBytes on my Win rig. Seems pretty solid. I've had all three of the other AVs you listed, and wasn't all that happy with them. Thanks!! I'll take a look at the link you provided!