Here is a list of very good and reliable security and cleaning tools:
CCleaner - removes junk and speeds up your pc
Clean Master - removes junk and speeds up your pc
Adw Cleaner- removes any adware from a pc
Malwarebytes Anti Malware - great malware detection tool, this will spot any infections and remove them
Spybot Search and Destroy - similar to Malwarebytes, but takes longer to scan
Glary Utilities - cleaning software and also comes with a virus scanner
Malwarebytes Anti Rootkit - removes rootkits and repairs damage
Kaspersky free scan - finds and removes threats and infections
Links (sorry not in order):
http://www.malwarebytes.org/downloads/
https://www.safer-networking.org/
https://www.piriform.com/ccleaner/download
http://www.cmcm.com/en-us/clean-master-for-pc/
https://toolslib.net/downloads/viewdownload/1-adwcleaner/
http://www.glarysoft.com/
http://www.kaspersky.co.uk/security-scan?icid=topmenu_hp_kss_uk
Hope this helps. Remember to clean after a scan and for Malwarebytes scan twice to check if the virus/malware has gone.