If you see the error, "boot configuration data store could not be opened" here are a some common reasons and solutions:

If the message that follows this is that it cannot be found, try running the following command:

bcdedit.exe /CREATESTORE

If the message that follows states that "Access is denied" then (as with the above command) you must keep in mind that BCDEdit requires admin privileges so you will need to run this in an elevated console window. To open a command prompt with admin privileges...

1) click start > all programs > accessories

2) right-click on the command prompt shortcut and choose "Run As Administrator"

For a bit more on BCDEdit, see:

Boot Configuration Data Store and/or
BCDEdit Command-Line Options.

VistaBootPRO is a freeware solution that aims to make editing the BCDEdit file much easier. If you are technically challenged or are frustrated with the tools provided, check it out at http://www.pro-networks.org/vistabootpro/