Oracle Sysdate Problem

When One Day my Oracle (working) database was stuck , I restarted Oracle database through OS Service instead of restarting Server Machine. From then onwards 'sysdate' was not working. Whenever I was querying

Select Sysdate from dual;

Output was ---- 23/06/2008 12:03:19 PM

Then wandering through Google i found it can be overcome by Altering FIXED_DATE parameter by running command as SYSDBA

ALTER SYSTEM SET FIXED_DATE='2008-06-25 10:06:09 AM' ;

From then onwards whenever i use this query

Select Sysdate from dual;
Output was ---- 25/06/2008 10:06:09 AM

This made me crazy for more than 2 days .After restarting Server Machine on 28th and then ALTERING FIXED_DATE TO NONE (ALTER SYSTEM SET FIXED_DATE=NONE).

After then Select Sysdate from dual; gives

Output was ---- 28/06/2008 12:06:09 PM

Thus next day i checked sysdate it was working fine as of OS date.

and thus the crazy days come to an end