Luckily it’s an easy fix. If you aren’t sure what we mean, we’re referring to this dialog:

If you want to do the same thing in Windows Vista, we’ve also got you covered there with a registry hack.

Reset Open/Save Dialog Choice in Windows XP

Open up a file explorer dialog and head towards Tools –> Folder Options.

Then use the File Types tab page to figure out the type of the file that you are trying to reset this for. The person’s PC I was fixing was having issues with zip files, so I went for that extension, but it should work for Excel, Word, etc.

Click the Advanced button, and then check the box for “Confirm open after download”. If it’s already checked, then uncheck it and re-check it again.

At this point your downloads should start prompting you again, and you can finally figure out where you downloaded Firefox to.