Where do I start? My Window 8.1 crashed and went through a "refresh" cycle. Reloaded VIRB Edit but it now has no clips or libraries. My clips are on an external drive and the (I hope all) *.fit files are on my hard drive.
Your database lives at C:\Users\<your username>\AppData\Roaming\Garmin\VIRB Edit\Database. If that folder does not exist anymore, you will have to re import your videos manually. To do this, you'll notice a an icon with an arrow pointing down next to the "Clip Library" text on the bottom left of the application. Alternatively, on the welcome screen, after you skip the intro video, there is a big "Import clips" button. Both will take you to a screen that says "Connect a Virb to start importing" and subtext that says "Import Other" Click import other, and you will be able to browse for videos you want to import from your computer. Multiple selection is supported, so you can select all your videos at once for import.
Getting your GPS data associated with the right file is going to be time consuming depending on how many videos you have. Once you have added a clip to a video project, under the edit tab there is a button that says "Add GPS..." Select that, and on the left side of the screen there will be a link that says "manual selection", click that and either drag and drop or browse to your fit files. You can also do multiple selection here, and you can click each imported file to see a map of where it is, which should help you find which fit file goes with what video. Unfortunately you will have to repeat this process for each video in your collection.