ORACLE INSTALLATION PROB

This is not recommended as an easy way to fix problems, especially common ones. Only create a Clean Machine as a last resort, and only if you want to remove all Oracle products from your system. Complete the following steps to create a Clean Machine.
The following Clean Machine instructions assume an OFA (Optimal Flexible Architecture) structure.

On Windows NT:
1. Ensure you are logged in as a user with Administrator privileges.
2. Using regedit (at the command prompt, type regedit), go to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE and delete the ORACLE key.
3. Delete HKEY_LOCAL_MACHINE\SOFTWARE\odbc.
4 Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services, and remove all keys under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services that begin with ORACLE.
5. Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\Application, and remove all keys under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\Application that begin with ORACLE.
6. Close regedit.
7. From the Control Panel, open System.
8. If JRE was installed by Oracle, remove the %ORACLE_HOME%\BIN path and the JRE path. For example, you may see a path similar to this one: C: \ORACLE\ORA81\BIN;G: \Program Files\Oracle\jre\1.1.7\bin. Go to Start > Control Panel > System > Environment tab. Click on the system variable path and modify the path.
9. Delete Icons from : \Winnt\Profiles\All Users\Start Menu\Programs\Oracle - and : \Winnt\Profiles\All Users\Start Menu\Programs\Oracle Installation Products. Where is the previous HOME name.
10. Delete : \Program Files\Oracle (from the Windows NT Explorer or from the command prompt).
2. Delete all ORACLE_BASE directories (You can find the Oracle homes listed in HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\ORACLE_HOMES).
Also See my hot new discussion named: ORACLE INSTALL/REMOVE(ANY)