Based on my two decades of IT experience across England, India & Australia, I would strongly recommend the use of the following freeware to keep your home computers secure:
AVG Free Antivirus – This product essentially takes care of viruses & trojans
Spybot -Search & Destroy – This product essentially takes care of of spyware, hijackers & trojans
Please click on the links above to download them as they are both free products which are tried & tested and deployed by us on a regular basis. Both products come with free updates and while AVG does a regular update and check, Spybot needs to be manually updated by selecting the option when you open the program and you need to manually perform a search and destroy check preferably every week. Both products need to be installed simultaneously and work in tandem very well.
Please ensure you remove any other antivirus(ie. Norton, Mcafee, Trend Pccillin) or anti spyware program prior to installing them as they may interfere and conflict causing the PC to hang.