Hi Prakadesh,
Try these steps.
1. Stop and disable the service of current SIA. You can do it from start-->run services.msc. Double click the SIA service and change the status to disable.
2. Login into sqlplus and drop all the CMS tables.
3. Create a new SIA pointing to Oracle from the CCM.
4. Start the new SIA and check if all services come up and you are able to login into Manager servers.
If this does not work, check the event viewer for error messages.
Regards
Chinmaya