Windows 7 Setup.exe install is not supported ( but also VISTA , Windows Server 2008 / 2008 R2 )on ConfigMgr 2012 SP1. With SP1, you need to use a WIM installation unless you’re installing Windows 8. It was mentioned here :
The build and capture task sequence was updated to apply an operating system image instead of running Setup.exe for installation. You can still run Setup.exe for Windows 8 deployments by editing the task sequence in the task sequence editor.
If you want to use the Windows 7 install.wim, find some instructions here to make sure the OS ends up on drive C:
When doing build and capture for Windows 7, you will need to first import the Windows 7 install.wim, which can be found in the sources folder on the Windows 7 installation media.
Once you have imported the install.wim as an available Operating System Image package, then you can update the build and capture task sequence to use the image instead of Setup (in my screenshot, I’m using the Windows 8 install.wim, but Windows 7 works the same way).
Now with Windows 7, there are some additional considerations required to ensure the installed/captured image ends up on drive C: (because the Windows 7 install.wim was captured using drive D: originally). You must add a Set Task Sequence Variable step before the Apply Operating System step that sets OSDPreserveDriveLetter=False.
Finally, you need to make sure that any partitions that come before the Windows partition are configured to not assign a drive letter.
This will ensure the Windows partition is assigned the first drive letter (C:) when the OS is booted. Once the image has been captured, it will already have the Windows partition captured as drive C:, so none of these additional steps are needed when actually deploying the image.
Hope it Helps ,