Microsoft Security Essentials
Provides real-time protection for your home PC that guards against viruses, spyware, and other malicious software. Microsoft Security Essentials is a FREE download from Microsoft that is simple to install, easy to use, and always kept up to date so you can be assured your PC is protected by the latest technology.
Malwarebytes
Malwarebytes is a site dedicated to fighting malware. Malwarebytes has developed a variety of tools that can identify and remove malicious software from your computer. When your computer becomes infected, Malwarebytes can provide the needed assistance to remove the infection and restore the machine back to optimum performance. FREE!.
Recuva
This program allows you to search a hard drive for deleted files or folders and attempts to restore them. When using Recuva you can specify the types of files that you wish to recover and either scan a particular hard drive or a particular folder. If a file is able to be restored, Recuva will list them and allow you to restore them.
ShadowExplorer
ShadowExplorer allows you to browse Windows Shadow Volume Copies created by the Windows Vista, Windows 7, Windows 8, and Windows 10 Volume Shadow Copy Service. When these Shadow Volume Copies are created, they also create copies of changed data files on your computer. ShadowExplorer allows you to use the Shadow Volume Copies to restore files back to previous versions or even to restore a deleted file.
FREE!