You shouldn't have any problem at all installing win 7, if your NB originally had Win 8 then you'll have to turn off secure boot and enable CSM in your BIOS, Insure your booting to a UEFI USB Install media. All the info is
hereIf you want to clone to your new SSD I suggest you use Macrium Reflect many have succeeded cloning there 750 HD to 256 SSD
G752VY-DH72 Win 10 Pro
512 GB M.2 Samsung 960 Pro
1 TB Samsung 850 pro 2.5 format
980m GTX 4 GB
32GB DDR 4 Standard RAM
Z97 PRO WiFi I7 4790K
Windows 10 Pro
Z97 -A
Windows 10 Pro