Sometimes when you are opening a file it tries to open it in the wrong program. That may be because Windows associates certain file extensions (such as .pdf .bmp .jpg) with the wrong program.
To change what program is associated with a certain file type, open up windows settings by clicking on the start menu and then the gear icon.
Then click on "Apps."
On the left select "Default apps."
This will open up a basic list of the most common file types. (Mail, Web browsing, pictures) But if you need to change a specific extension file type, scroll down and click on "Choose default app by file type."
This will open a VERY long list of file extensions, they should be in alphabetical order. Keep scrolling until you find the ext that you would like to change.
When you find the file extension you are looking for, click on the currently used program on the right.
It will then present you options of different available programs that can be used for that file type. Select the one that you need.
As soon as you click that option it should change what program Windows tries to open that file type with.