Difficulty installing Windows 7 Ultimate

Your system has an 8th Gen Core CPU.  Windows 7 only supports up to 6th Gen Core CPUs.  The reason you can't get your ISO to run is because Windows 7 doesn't have native support for USB 3.0, so basically your system handles booting from the flash drive, and then when it hands USB control over to the Windows PE environment that loads, Windows PE can no longer see the flash drive it just booted from.  There are guides that cover injecting USB 3.0 drivers into the Windows 7 install media, but again that OS isn't supported on that system anyway.  Chances are good that things like the touchscreen and touchpad will only work partially or not at all, and you won't find Windows 7 drivers available to fix that.

No way you'll be running Windows 7 on this hardware -- even if you can get it installed, once installed -- it won't update.

All CPUs beyond the Intel sixth generation are Windows 10 only - and yours is an eighth generation.  If you must run Windows 7, look for one of the few new systems still using the sixth generation CPU -- the Latitude xx80 still has a couple of options for you.  Nothing in the Inspiron, XPS or Vostro line will.

Details here:

http://www.dell.com/support/article/us/en/19/sln304217/microsoft-windows-operating-system-support-for-intel-kaby-lake-processors?lang=en

https://support.microsoft.com/en-us/help/4012982/the-processor-is-not-supported-together-with-the-windows-version-that

Go to BIOS keep this setting

1. Secured Boot: Disable
2. Legacy: ON (Dont USE UEFI)
3. Use USB Port 2.0 (Black Color)

After saving the bios put the Windows 7 USB and press f12 or FN+F12 one must work and u must see the boot option select USB and continue.

Accepting all of yours as a solution, I purchased a new copy of WIN 10 PRO and installed at  a miraculous speed. No trouble at all. But I cost me  a fortune in terms of the software.

Yet I have a complaint about the brightness of the display which looks hazy, sort of off-white not shiny white LED. It is set at maximum though! May I know the reason? or have any solution to improvement.

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@debonylwrote:

Accepting all of yours as a solution, I purchased a new copy of WIN 10 PRO and installed at  a miraculous speed. No trouble at all. But I cost me  a fortune in terms of the software.

Yet I have a complaint about the brightness of the display which looks hazy, sort of off-white not shiny white LED. It is set at maximum though! May I know the reason? or have any solution to improvement.

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Did you install drivers starting with the chipset?

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