Her are the steps to migrate on NT/2000 Platform :

- Shudown all services for 8.1.5
- Install 8.1.7 on the same home of 8.1.5
- During installation choose custom , you will find that many components are marked with "upgrade " this means that Oracle is going to upgrade this product to the new release so leave it as is , choose all other new componenets to install .
- Start Installation , It will take a while ( It took 35 Minutes on PIII 700 + 128 M Ram + SCSI HARD ) .
- Restart Machine
- Start Listener

DO THE FOLLOWING STEPS TO UPGRADE EVERY DATABASE IN THE BOX :

- Open DOS Window
- Set Environment variable to the SID you want to upgrade
- Start Server manager
- Connect internal
- Run the script needed to upgrade the database , this script usually look like this :u0801050.sql ,, tha path is :
%Oracle_Home%ora81\rdbms\admin\u0801050.sql

Do this steps to update every database .

GOOD LUCK