Hi,
i had tried to install oracle 9i on this same machine but couldnt complete the installation bcause i didnt have sufficient space on my hard disk. Since the installation didnt complete i had deleted the folder(oracle home) which was D: partition. Now, I have intalled 8i on C: partition. I hope this info helps. Also i went into registry but they are too many folders with the name home..like home0 oracle_homes etc... I am attaching the picture of registry as well. I went to hkey_local_machine > software > oracle > Home0 ... As u can see from the picture it shows the previous oracle home which was on D: partition....