How to convert my dual boot desktop system (WinXP and Win7) to single Win7 system before doing Acronis True Image Plus backup.

I no longer need the WinXP installation on my dual-boot WinXP/Win7 system, so I want to remove the old harddrive C: that XP is installed on, and boot directly into Win7 that is installed on a newer separate drive D:

However, the Win7 BCD (boot configuration data) is read at boot time from the C drive. How do I make the Win7 D: drive boot up without the C: drive? I presume I have to move the BCD info to the C drive, but how is this done?

Thanks for any assistance anyone could provide.