It may pay to check in Control panel, then remove the old version, then re-install new version Windows Defender. Alternatively, just use the link above, and follow the instructions, and see if it overwrites the old copy.
I have deleted the old version but could not install the latest version before deleting nor can I download now. I have saved the download on my desktop. I am getting a message up saying Windows Defender requires Windows 3.1 or later to view a list of all installation requirements visit Microsoft. Not sur what to do when I click on Microsoft.
I have clicked on the link, it takes me to a page that is just as confusing I have to read it and agree but where do I click onto to to say I agree? Also the print is so faint and half the size of this print it is difficult to read. Not sure how to make the print larger, or darker. Could you please explain telling me what I am supposed to click on. Calling it a day, maybe tomorrow will bring me luck with downloading MSspyware.
To enlarge the print hold down Ctrl and use your wheel on the mouse. That will enlarge or lessen the size of the page. The site shows that you have to verify windows first before you can download windows installer 3.1 .