Unplug all other HD's, boot the Windows 7 DVD to
Clean Install Windows 7. How to Boot your Computer from a Bootable CD or DVD
If the SSD has anything on it, wipe it first with
Diskpart Clean Command.
If disk still fails to boot, check all of your connections and cables, set SSD first to boot in BIOS setup and trigger the DVD using the one-time BIOS Boot Menu key at boot.
On a wiped HD the installer should autostart. If not you have booting problems with the DVD. Try writing the latest ISO to flash stick to boot and install, from Steps 1 and 2 here:
Clean Reinstall - Factory OEM Windows 7
You can of course use retail OEM version on a new build.