do one thing
First stop all the services running related to oracle.
Delete the folder where ORACLE is installed (if gettin error while deleting the folder (unable to delete) use the software unlocker to unlock the folder from here
http://www.softpedia.com/get/System/...Unlocker.shtml Then delete it (oracle folder ofcourse)
), Using Regedit/regcleaner/similar softies remove all registeries entries related to oracle.
Now install the Oracle form the very begining.
DO NOT DO THE CUSTOM INSTALLATION BY YOUR OWN IF U DONT KNOW WHAT YOU ARE DOING.
MAKE THE INSTALLATION AS "ENTERPRISE" WITH ALL DEFAULTS