This computer came with Windows 10 installed and I have separately purchased Windows 7 directly from Dell. The Windows 7 software from Dell will not install on the Dell Inspiron 7559 complaining that at a DVD driver is missing.
I have followed a Microsoft suggestion to make a bootable USB from the DVD and install from that instead. Same problem. I still get blocked by the demand for a DVD driver.
After some investigation, I found a youtube video that suggests the problem is related to USB3. I don't know of any USB2 ports on the 7559 as they are all USB 3.0 from the specs.
How can I get this software to install? Several calls to Dell Support has not been able to help.
You will need to change the bios settings with UEFI BIOS.
Press the F2 key when booting to access the BIOS
Boot mode should be selected to UEFI (not legacy), secure boot off. If the system is not selected to boot to UEFI, change it from BIOS or F12 menu.
Windows 7 reached End of OEM a while ago and End of Retail sales a long time ago therefore its extremely unlikely Dell would sell a Windows 7 license separately...
Dell may sell the system with Windows 10 Pro and Downgrade Rights to Windows 7 Pro but this is extremely unlikely with an Inspiron (home sector model). If they did sell this configuration then the Skylake .iso should be available: