A little while ago I installed Kaspersky anti viral program - may be wishing I had not!

A folder of my wife has a large number of files, all saved as .doc or .docx files

Something has changed the .doc and .docx files to .rtf files.  I am not sure if this change is as a result of some keyed action on our computer, or a system change brought on by Kaspersky.

My questions are twofold  :-

Is there likely to be a setting within Kaspersky that "selects" .rtf as the file save format ? [ even though the files were all created in M/S Word, and saved as either .doc or .docx files]

Is there a way to reverse the whole folder from .rtf to .docx ?

Thanks in advance to my NAT friends.