I successfully installed the MySQL ODBC 5.1 driver for Windows:
But unfortunaly it doesn't appear in the ODBC Data Source Administrator of Windows (yes, I even did a log off + log on):
Nothing you've said clearly indicates whether you're using the 32-bit or 64-bit ODBC Administrator, nor whether you instlaled the 32-bit or 64-bit MyODBC driver, but this is almost certainly the root of your problem. Note that both the 32-bit and 64-bit program are named the same, odbcad32.exe. The difference is in their counterintuitive directory location -- System32 (for 64-bit components) and SysWow64 (for 32-bit components).
you may be hitting an old but recurring issue with minor corruption in the Windows Registry.
The corruption takes the form of entries containing this 4-character string --
These entries aren't visible anywhere except Registry export files -- but they can lead to a number of undesired behaviors.
NOTE: On a 64-bit Windows machine, there are naturally some complications tied to the 32-bit Registry. This Microsoft KB article may be sufficient to get you through these.
I suggest that you use the 64-bit Registry Editor to export the following branches (where these entries tend to be found) --
Edit these files in any text editor (Notepad or Wordpad are generally fine), and delete all lines which consist of that 4-character string, above. Then, delete the Registry tree segment(s) you exported, and import from the edited files -- thereby restoring the tree segment(s), minus the corruption.
usually forget that the 32-bit components do not work natively on 64bit systems and Microsoft helps the confusion by naming the folder SysWOW64 for 32-bit