SQL Server 2005 on A/P cluster

Question

I have a clustered two nodes ( A\P) servers which are HP ProLiant DL360 G5 2.66GHz  dual processor  with 16GB ram.

It has windows 2003 sp1 64 bit and SQL 2005 sp2 64 bit.    Everything looks good and all configurations seem set up correctly. But, the SQL server in SQL group stop and re-run every night between 10:00 and 10:30 by cluster managment. I am getting all symptoms that are posted in the above message.  What is very strange is why it always happens on a certain time of the day. Needless to say that we do not have any scheduled task on the server or SQL server.

 Your help would be greatly appreciated, since I am getting out of clue.

 

 Thanks