Dell Optiplex 7010 Windows 7 install hanging with SSD

Wondering if anyone has tried to install Windows 7 on an Optiplex 7010 with a Samsung 840 Pro SSD from the Dell Windows 7 installation DVD with success?

The setup is an Optiplex 7010 Ultra Small Form Factor that came with Windows 8 Pro - I've booted to that a couple of times and that runs ok. Replacing the stock 500Gb drive with a Samsung 256Gb 840 Pro SSD and attempting a Windows 7 install results in a permanent hang at the first Windows icon splash screen (after the initial install bar goes across).

No amount of fiddling with BIOS options helps which is the current latest (A14) as is Samsung SSD firmware (DXM05B0Q). Protected boot is off and the install DVD is fine - i.e. works elsewhere.

Any thoughts? I'm leaning towards an incompatibility between the Samsung 740 Pro drive and the 7010 - but its a pretty common drive..