unable to open DB

[adewri]

Windows

Reboot your system

Is it possible to do that ?? i mean

alter database close...

every time i try i get

SQL> alter database close;
alter database close
*
ERROR at line 1:
ORA-01093: ALTER DATABASE CLOSE only permitted with no sessions connected


SQL> select username from v$session;

USERNAME
-----------------------------------------------------------------








SYS

9 rows selected.

SQL>

How did you do that ??