Why doesn't version 5.2.7 install after download?

Downloaded version 5.2.7 to replace version 4.4 and it appears in download folder. Double-click it, and install wizard appears, and says the install will happen and will "take a few minutes"but nothing happens. The status bar doesn’t move. After an hour, get message saying that the install has stopped and do I want to cancel it. I do. I try to do a second install and get message that another install is running, but see no sign of that. Am running Windows 10 and use Firefox as browser.
Any suggestions?
BobG

You need to uninstall your older copy of LibreOffice and Offline Helpfiles before installing new versions. I have had issues on Windows installing new versions of LibreOffice on top of older versions where it would just sit there. On my computers, the installer gets stuck on calculating free space when trying to upgrade LibreOffice on Windows.

Uninstall all older versions of LibreOffice and associated offline help files, reboot your computer, and then install the new version.