Reassigning drive letter for cloned system partition

Question

Since my primary Windows 7 partition (C:) ran out of space, I made a disk image with Seagate Disk Wizard (which seems to be a version of Acronis True Image) and restored the image to a bigger partition (J:) on another harddisk. After that, I added with bcdedit a new bootmanager entry with the information for the Windows version on J:\ and booted into that version.

Everything fine to this point, but how do I get rid of the old C:\ partition and change J:\ back to C:\?

I tried reassigning the letter from Windows within, which quickly resulted in very weird (yet interesting) behaviour, since I hadn't any C:\ anymore. I changed it back since it obviously doesn't work this way. Now, how do I do this correctly? And what happens to the 100 MByte System Restore partition Windows automatically creates on install? Its on another disk than my primary boot partition.

Solution

I did it the way Psycogeek suggested. Changed the registry values and rebooted into the desired installation. Worked without issues so far.

Comments

[Psycogeek]

support.microsoft.com/kb/223188 I am pretty sure this is still the way it is done in windows 7 , you get into the registry, and manually make the changes, which may require change the permissions and admin access and all. and make SURE that you dont overlap repeat and all that stuff, when you reboot the registry will set them.

[JdeBP]

Actually, you've cloned your boot partition. Understand what boot and system volumes are and what your Microsoft tools are telling you will become a lot clearer.