Oracle Database Discussions

Hi,

When i tried to startup my database in my PC i experienced the following errors.

SQL> startup nomount;
ORA-03113: end-of-file on communication channel

then again i startup the following happened
ORA-27100: shared memory realm already exists

I looked in the alert log file and i found the following

Wed Dec 27 00:05:17 2006
Errors in file D:\oracle\admin\premdb1\bdump\premdb1PMON.TRC:
ORA-00470: LGWR process terminated with error

Wed Dec 27 00:05:17 2006
PMON: terminating instance due to error 470
Instance terminated by PMON, pid = 940
Wed Dec 27 00:31:53 2006
Starting ORACLE instance (normal)

Can anyone tell me y this happens and how to resolve this.

Thanks in advance.

Regards,
Prem