I recently had corrupted membership data in one of my DNN websites. Even the host password got hosed, so I couldn't login and install a module to fix it. My backups had the same problem. Thankfully, the rest of the database content was ok. I went and looked for a Winform app, but couldn't find anything after a couple hours searching.
I banged out a quick app in VS2008 and C# to help me deal with this crisis. My stress and panic disappeared, for now I can deal with corrupted passwords. I wanted to give something back to the community, so I made the source and binaries available for free. The app is not fancy and doesn't have bells and whitles, but it will let you quickly deal with this stressful issue.
You can find the app in my blog. The link is below.
http://systemwidgets.com/Blog/tabid/61/ctl/ArticleView/mid/397/articleId/138/DotNetNuke-user-manager--Winform-App.aspx