How to Upgrade sqlserver2000 to Sqlserver2005(Sapb2005)

Hi,

How can i upgrade Sqlserver2000 to sqlserver2005 database.Previously i am working with Sqlserver 2000 Database now regarding requirement i had to upgrade Database in Sqlserver2005 without uninstalling Sapb12005 can anyone suggest me regarding this Issue.

very Urgent.

Regards

Nagababu