Ever had this happen? You have two different versions of Word installed — say, Word 2003 and Word 2013. You may have upgraded recently based on our advice about Microsoft killing support for Office 2003. You double click on a Word file — and it opens in the old version! How inconvenient. You’d really like Word files to open in new Word, but you don’t know how to make that work.

Or, you uninstall an app, and now opening a file tries to find the uninstalled app — instead of the new app that was meant to take the place of the old.

Changing file associations in Windows is convoluted and not at all as easy as it should be. (At least we’re not in Android, where you have to erase all of them and start over!) Luckily, we’re here to help.

In Windows XP:

1. Click Start.
2. Click Control Panel.
3. Click Folder Options.
4. Click the File Types tab.
5. Click New.
6. Type the File Extension in the box.
7. Click Advanced.
8. Select an association for the file type.
9. Click OK.
10. Click Close.

Try opening the document or file again.

In Windows Vista and 7:

1. Click Start.
2. Click Control Panel.
3. Click Default Programs when viewing by Small Icons.
4. Click Associate a File Type or Protocol with a Program. Wait for the list to finish loading.
5. Scroll down to find the file type you’d like to change. For example, .DOCX
6. Click it, then click Change Program.
7. Choose an existing program from this list.
8. Or, click Browse…
9. Browse to the correct application, then click Open.
10. Close the window.

Try opening the document or file again.

In Windows 8 and 8.1:

1. Press Windows Key + X.
2. Click Control Panel.
3. Click Default Programs when viewing by Small Icons.
4. Click Associate a File Type or Protocol with a Program. Wait for the list to finish loading.
5. Scroll down to find the file type you’d like to change. For example, .DOCX
6. Click it, then click Change Program.
7. Choose an existing program from this list.
8. Or, click More Options.
9. Scroll down and click Look for Another App on this PC.
10. Browse to the correct application, then click Open.
11. Close the window.

Try opening the document or file again.

Click Look for Another App on This PC if your desired application is not listed.

You’re all set! Feel free to re-associate as many files to their correct applications as you can. That way, you can double-click a file with confidence, knowing that the exact application you want will open the file.