Detection is only as good as definitions and definitions depend on submissions and internal testing by the vendor. Vendors also have different names so what one vendor calls something may actually be the same thing named differently by another vendor.
Please note that it may not be able to safely recover your mother-in-law's computer. Also, trojans like Kuluoz are back doors that steal information. As described by Microsoft, Kuluoz, for example, looks for files used by the browsers Firefox and Opera that may contain user names and passwords. It also looks for document files and spreadsheets, which it packs into an archive file. It sends the browser files and the archive file to a remote server. If the machine is recovered, it will be imperative that passwords for any online banking, credit card or similar be changed.