Boot

He only needs to disconnect the Vista drive and then install 7 - exactly as point 2. of my earlier post - which snifferpro kindly repeated.

There is a thread here where a user had a problem with a removable device causing the "The boot selection failed because required device is inaccessible " error. I noticed in your device management that you have some removable devices so disconnect them and try installing.

Disconnected one hard drive tried to boot on the other and get this message: Reboot and select proper boot device or insert boot media in selected boot device and press a key.

Might be he needs to login to Vista as Admin, not std user.
that is the only reason I can see he would not have permission to write to C:\ and install Win7 as dual boot.
it also takes a fairly experience operator to add the dual boot sequence.

I also agree with all other suggestions. but I think he will have major problems with the rest of it

disconnect vista drive, connect w7 drive to main connectors, run w7 disc, install on drive, place w7 drive as slave, and vista drive as master, boot up, enter BIOS and select OS to boot.

Now when I boot into the second drive I get: BOOTMGR is missing

You have to set your bios to boot from your DVD drive first in able
to install Win 7 to the empty hard drive.

You can also try tapping f8 at boot to get the bios boot screen and
select your dvd drive to start the install

I did set my bios to boot from dvd.

can you tap f8 at boot (keep tapping) and see if you get a bios boot screen
where you can select the dvd drive to boot from