First, make your recovery media, because installing Windows 7 will destroy the factory install of Windows 8.  You will need it if you ever plan to use the factory installed Windows 8.

To install Windows 7, you must turn off UEFI and secure boot and boot in legacy mode.  Then you can use an external CD or a non-GPT flash drive to install Windows 7.  You will need to take the hard drive back to bare metal (delete EVERYTHING on the drive) to do the install. 

Also realize that Dell does not have drivers for Windows 7 on this model - you will need to search for all the drivers you need from the component manufacturers, and will likely face the fact that some hardware in the system will not have Windows 7 support.  That is to say, you will wind up with a system that's only partially functional when you install Windows 7 -- at a minimum, you will likely lose the ability to use the touchscreen (I believe you'll find others have reported there is no support for the touchscreen under windows 7 -- and even if you can get it to work in a rudimentary way where others have not, windows 7 is not designed as a true touchscreen OS -- the touchscreen support is highly driver dependent;  see above for the Catch-22 there).

hello, thanks for listening my equipment is not starting the operating system it is on a screen with the windows logo and will not go ahead, I'll change the option I suggested for legacy and see if it work and put in sequence, would you like me actually stand one print screen the problem? I turn over any option in the bios or change something so that it can proceed with the boot?

Windows 7 in Legacy mode did not work, I will reinstall windows 8, even though he did not start the boot is on the screen and the fish does not come out of this, the diagnosis of DELL not report any problems. have something I can do to try to solve this problem.

Removed the SSD and installed it in a USB adapter on my pc, I formatted the SSD, I copied the files from the windows 8 CD to the root of the disc and he became active by diskpart, it booted normally on my pc, turned off the pc, installed the SSD in notebook again and the system will not boot, went back into the BIOS to UEFI boot mode and still the operating system does not start, it is on the screen and not trying to start it out, restarted, went into the bios and I disabled all USB ports, the Intel Smart, and TPM also have disabled the Intel VT, but even so the notebook does not start, would have something else to do, might be a problem with the bios version a05 and am in an update to a08, but I can not upgrade without entering the operating system.

You have disabled UEFI and Secure Boot? See notes at the bottom here:

http://dellwindowsreinstallationguide.com/a-clean-install-of-windows/ensure-you-have-the-correct-sata-configuration-in-the-bios-setup-for-your-configuration/

What is the SATA operation of your system?

http://dellwindowsreinstallationguide.com/a-clean-install-of-windows/ensure-you-have-the-correct-sata-configuration-in-the-bios-setup-for-your-configuration/sata-operation/#VarB

Have you also disabled USB 3.0 functionality?

http://dellwindowsreinstallationguide.com/a-clean-install-of-windows/ensure-you-have-the-correct-sata-configuration-in-the-bios-setup-for-your-configuration/disable-usb-3-0-functionality/

Windows 7 doesn't have native USB 3.0 drivers and so often won't install properly unless USB 3.0 functionality is disabled.

Hello,

I took several tests, I performed the procedures you told me, and even then the machine does not work. So googled the problem really is with the Bios version A05 or earlier version has a bug that causes this defect, but the company sent my laptop www.compuword.com.br and they corrected the problem almost immediately, within 3 hours my equipment was finally working, no need to open it or exchange parts, were very attentive and almost solved the problem of readiness, I recommend them to anyone who has or is experiencing this type of difficulty.

there is the hint. Thanks for support