When you say you "reseted" (reset) windows, I believe you mean, you had to reinstall windows, which would have knocked out everything on your hard drive. If I'm wrong there, please explain what you mean by "reseted (reset)."
One recommendation for everyone is to periodically save their Opera profile, ideally to an external drive like a flash drive. Go to the Opera menu, and click on About Opera for its location in your computer. The reason one needs to do that is to cover the exact situation you seem to describe.
If you made a copy of the profile, it would be simple now to restore the speed dial items and the bookmarks, by simply copying (let's say from the flash drive) the bookmark file and speed dial file into the profile of your current version of Opera 28.
Assuming you haven't, I'm not sure exactly what to do. If you did a re-installation of Windows, and don't have a backup profile saved to an external drive, you may not be able to recover the bookmarks and speed dial items. However, one possibility here. On bookmarks, do you have your bookmarks on an Ipad or Ipod version of Opera (Opera Mini or Opera Coast), or on Opera mini in an android tablet or phone. If so, then Í'm wondering myself whether you might be able to move them to your desktop Opera through the sync feature in Opera 28. I'm not an expert in how to do it, but from my understanding it may be doable for bookmarks. In that regard, I know you can sync your bookmarks from desktop Opera to your mobile devices. The only part I'm not sure about is whether you can sync backwards from the mobile device to the desktop Opera. I leave that to others to comment on that. I don't believe the sync feature covers the speed dial.