After taking my slow laptop to a local PC repairer they not only upgraded Windows 8.1 to Windows 10 but also installed the free version of Malwarebytes. It can only be safely to download from https://www.malwarebytes.com/mwb-download/ Beware other sites are liable to install more malware instead. The shop used its free scan and removed 20 malware I then used it on this old Windows 7 and removed 72. It seems much of today’s so called antivirus like AVG installed on both fails to detect malware. So why not use the current 14 day free version to run a scan. You may be horrified to see what malware it finds. If so I suggest you buy the full version for a mere £29 or £40 for two PCs.
Once it finds malware it makes it harmless by moving it to Quarantine. I strongly advise you to then use the Delete option anyway to remove it completely. That is if only to be sure any other malware it finds later is obviously new and not old. Meanwhile it blocks any more malware and warns you. A pal of mine who visits sites to download help to create games got so fed up with the numerous warnings of blocks he has disabled just the warning notifications.
The makers of Malwarebytes claims it makes other antivirus unnecessary I wonder if any of you agree.