I guess you are using Windows 10 (9 never really existed). But you have a new OS install.
The downloaded files may be going to a hidden folder- if directed elsewhere by the reinstalled browser. Or perhaps the file extensions of those files might be hidden (which is a windows setting to un-hide them. (Have to uncheck hide known file extensions.
(To un-hide folder extensions: Click the "Folder Options" item in the popup menu that appears. A dialog box appears. Click the "View" tab at the top of the window. Look for a setting "Hide file extensions for known file types" and uncheck the box beside it to disable it and voila the file extensions will be visible).
Also might want to un-hide all of the folders/files:
To do this: View hidden files and folders in Windows 10
Open File Explorer from the taskbar.
Select View > Options > Change folder and search options.
Select the View tab and, in Advanced settings, select Show hidden files, folders, and drives and OK.
(To hide again, go to the same but click Don't show hidden files, folders or drives.)
So #1, have to establish where your download files are going and then have the ability to see them.
Norm