Oracle Database Discussions

Hello,

I am using oralce 10.2.0 on win 2003 server. my
Automatic Shared Memory Management is Enabled. I take backup of spfile using

sql> create pfile from spfile;
 

my pfile created in C:\oracle\product\10.2.0\db_1\database\initneo.ora

now i do some change like

SQL> alter system set sga_max_size=1740M scope=spfile;

System altered.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORA-00385: cannot enable Very Large Memory with new buffer cache parameters

then i try to restart my database from backup of spfile but it is useless

SQL> startup pfile='C:\oracle\product\10.2.0\db_1\database\initneo.ora'
ORA-00385: cannot enable Very Large Memory with new buffer cache parameters

then i start my database with default pfile in 

C:\oracle\product\10.2.0\admin\neo\pfile

the error is not my concern.

1. i want to know the way to take backup of your spfile so i case of error you can restart database from spfile backup. in my case which is not working.
2. how can we get our database back if spfile and pfile both are corrupt.

Thanks
umesh