The monitor must have more than 16 colors. If the monitor has only 16 colors, OUI won't come up. This is because the OUI uses JDK which in turn does not support monitors with 16 colors.
If the version is older, installation may hang on Windows NT while registering one of the DLLs. This hang occurs because of Microsoft's known regsvr32 problem with silent registration.
The workaround is to terminate teh regsvr32 processing using Windows NT Task Manager. Terminating this process allows the installation to continue. You can register the DLL later by executing the following command from the command prompt
C:\> regsvr32 ORACLE_BASE\ORACLE_HOME\bin\OraOLEDB.dll