Ok, I bought the ApprenticeHD License awhile back, once I installed Houdini I was able to run it with the license and every thing was working perfectly with no problems. But when I had to reinstall my Operating System, I had to reinstall Houdini. But now my Apprentice HD license doesn't appear no matter what I do. I even tried manually enter keys and it says it installed successfully but it didn't do anything.

Please tell me how to fix this. There has to be a way, just in case something like this happens. Or not?

EDIT: Oh and the Apprentice HD License does appear on the Online Services where it lists all the licenses I'm entitled to.

usually, to reinstall the licenses you need to follow these steps:
http://www.sidefx.com/index.php?option=com_content&task=view&id=1209&Itemid=273#lost [sidefx.com]

But it sounds like you already have gone through these steps. So perhaps the SERVER code has changed. To resolve that, you can send the output of the View > Diagnostic Info in the License Administrator to the apprentice@sidefx (or support@sidefx