Make sure ORACLE_HOME\bin is in PATH:
ORACLE_HOME\bin must be in the user's PATH environment variable. Go to a DOS prompt, type "PATH" and see what your path is. It could look like this:
PATH=C:\ORAWIN95\BIN; C:\PROGRA~1\MSOFFICE\OFFICE;C:\WINDOWS;
You could either go through the Control Panel to alter the PATH, or edit AUTOEXEC.BAT in the root c:\ folder.
If you are having trouble connecting, put the Oracle Home as the first thing in the path, before any other tools or variables.
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Step (2). Determine your ORACLE_HOME value.
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Check the ORACLE_HOME value. Look in your windows registry, via Start|Run|Regedit, drill down to HKEY_LOCAL_MACHINE\Software\ORACLE. There should be an entry for ORACLE_HOME, as well as many other entries. Like this:
[HKEY_LOCAL_MACHINE\Software\ORACLE]
"ORACLE_HOME"="C:\ORAWIN95"
In this case, my ORACLE_HOME on this Windows 95 box is "c:\orawin95".
If you have Oracle8i or an Oracle product called the "Home Switcher" which gives you the option of changing ORACLE_HOME settings to reconfigure your computer for access to several different types of Oracle Databases, then your registry settings will look like this:
[HKEY_LOCAL_MACHINE\Software\ORACLE\ALL_HOMES]
"HOME_COUNTER"="1"
"DEFAULT_HOME"="DEFAULT_HOME"
"LAST_HOME"="0"
[HKEY_LOCAL_MACHINE\Software\ORACLE\HOME0]
"ID"="0"
"ORACLE_HOME"="C:\ORAWIN95"
"ORACLE_HOME_NAME"="DEFAULT_HOME"
When Oracle connects, it will look in ALL_HOMES for the "LAST_HOME" value, which in this case is zero "0". It appends zero to "HOME" to produce "HOME0", then it looks in HKEY\Software\ORACLE\HOME0 for the ORACLE_HOME value.
*LAST_HOME should point to the correct Oracle Home in the path (step 1).
