Someone asked: where are setting stored?

Most connection specific information is stored in your .tnt connection files. Just copy these files to the new system and that should give you a fresh start. There are some options, specifically on the 'Global' tab of the Options->Properties dialog that are stored in the registry and are not easily copied to the new system. You could, however, export that part of the registry and import to the new system, but that would not be recommended for most users. If you're interested though, try exporting the following branch of your registry:

HKEY_CURRENT_USER\\Software\\Celestial Software\\AbsoluteTelnet

Let me know if your Media Center problems go away!