I installed Oracle8i on my computer, windows 2000 advanced server, right after I finished the installation, I created a new repostory, but I could not start Oracle Management Server. Now, I tried to create a new repostory or delete the old one. but I could not connect the database, it shows:

ORA-01034: Oracle not available
ORA-27101: Shared memory realm does not exist

???? Do I have to reinstall oracle again or there any other way to fix the problem? Thank you in advanced