I have had to hang on to my old ActivePerl 5.6.1 binary build 638 in order to use Win32::ODBC on my laptop with Windows(tm) 7 Home Premium O/S. What I found is that the C:\Windows\System32 directory (default for ODBC Administrator Utility accessed from the Windows Help System) contains no ODBC Drivers. But the C:\Windows\SysWOW64 directory does contain ODBC Drivers. So when I run the ODBC Admin Utility from that directory(via Windows Explorer), I do get a list of the Drivers installed (MS-Access, etc.). But this is still not enough. Even though I manually place C:\Windows\SysWOW64 in my path, I still cannot get the latest ActivePerl (5.26.1) Win32::ODBC module to work. It must have been altered sometime after 5.6.1 ActivePerl was released 15 years ago. I have not upgraded my Perl since then because of this long standing bug. My guess is that someone hard coded the Win32::ODBC module to look for drivers in C:\Windows\System32 alone.
Failed: Microsoft ODBC Driver Manager Data source name not found and no default driver specified