Loss of ODBC source

[StevenK]

Not so much a query about Delphi - more so about the finished application developed with it. We have an application developed in Delphi 5 that works against a SQL server 7.0 database on a server from the local client machines. We are using an ODBC connection through which we connect the database component and then respective data-aware components. Two machines on our site have been found to lose their ODBC connections that were set up to access the database. We are then unable to re-create the ODBC connection through the ODBC Source Administrator - after indicating the server-name and entering a user-name/password for authentication the machine hangs after clicking the 'Next' button. The only way we have found to re-create this ODBC connection is by a re-install of the operating system. This problem is tempremental in the sense that one day the ODBC source is present and the application can be used and then the next day the ODBC connection is no longer there for use. The two machines in question have Windows '95 and Windows '98 as their operating system - other machines with the same OS do not have this problem.
Does anyone know of any software that would cause the loss of ODBC source connections or can anyone provide us with some pointers ?
Thanks in advance.
Steve