I am talking about the bundled one, so when i upgrade to vcenter server 5.1 it will not upgrade the DB to 2008 r2 express? from what i can see on the matrix only Microsoft SQL Server 2008 Express (R2 SP1) - 64-bit is supported. I guess when i start the installation it will know i already have a vcenter installed on this machine and it will perform an upgrade of the system and install the 2008 r2 express over the 2005 and i can choose to keep existing DB or create a new one?
/Stefan