I have a windows 7 64 bit desktop with some 32 bit applications that need to connect to an oracle database. I went to SYSWOW64 and set up an ODBC driver, tested it, and connected to one of the 32 bit applications with no problem. When I tried to connect MS Access with the same ODBC connection I get a TNS error like it can't find the tnsnames.ora file. I have a full oracle client loaded and only one tnsnames.ora file on the machine. I've tried pointing the ODBC driver path to SYSWOW64s' odbcad32.exe, which seemed to help some others, but it didn't work for us. (We changed it back to point to the original location.)