I am a beginner in oracle ...i installed oracle 8i on win xp(128 mb RAM).I connected to Oracle for the first time using username:scott and password:tiger .but now when i try to connect to oracle using same password/username, it displays mme the following error:-

ORA-12560: TNS protocol adapter error

Please tell me as to what to do??? I will be really thankful to you...Please help me!!!