Recently while visiting family in Louisiana, I was tasked with fixing three PCs that had developed symptoms of viruses, etc...  The first, my mother-in-laws, was easy Spybot and MalwareBytes made short work of the infections and it was back to normal in no time.  The second, my granddaughter's laptop, had been used by her boyfriend and was also loaded with Malware, same fix restored everything to normal.  The third one , my daughter's PC, resisted the efforts of Spybot and MalwareBytes  The disk with the operating system was virtually full, I couldn't do any disk maintenance actions.  Exploring the hard way I found that there were 20 gigabytes of files I could not find.  On the last day after a good night's sleep, I remembered to display all the hidden files, and finally I found the offenders.  They were needed hidden in a folder named MobilSync, that folder nested two levels down from the folder.  Apple Software.  My daughter's iPad had been linked to her home network and had created massive files on the PC that filled the hard drive used by the operating system.

  Must be a new strategy by Apple to kill the PC.

I removed the files and the PC works again until the iPad sneezes again and the PC catches pneumonia.

ken clark