Can't dual boot windows 7 with windows 8 ?

I just bought a new laptop with pre-installed Windows 8 . I tried to install windows 7 in the second partition so i can use both 7 & 8 . Used windows 7 64x DVD , i started the installation from windows 8 . It went well until restarting where i got two options "windows 8" or "windows setup rollback" which it stops at "starting windows" logo from windows 7 !! ... i tried to boot from the beginning from the dvd(second time with usb)..it didn't boot..instead i stuck again at "starting windows" logo. so i can't even boot from the dvd .

I disabled the Secure boot from the beginning ... i have been searching for a solution but nothing worked .

Do I have to delete all the partitions on the disk then install windows 7 ??..if i do...how to keep windows 8 (i don't have windows 8 DVD) ?? .... please notice i am not an expert in these things so please make it detailed.

if i can't even boot

i have Toshiba Satellite C855D

I have GPT drive and UEFI bios mode (don't know what either of that means but read it might be a problem).

1) Downgrade to Windows 7.
Downgrade Windows 8 to Windows 7
Warning you must have the UEFI/BIOS firmware setting in Step Three set.

Make sure you read the NOTE at Step three.

2) If Using a USB Pen drive on a PC with a UEFI BIOS.
USB Pen drive need to be formatted to FAT32 as in
UEFI Bootable USB Flash Drive - Create in Windows
Take note of Step 11 for Windows 7.
Also you will need to use a USB 2.0 port, as there are no USB 3.0 drivers in Windows 7.

As Toshiba has no support for Windows 7 x64 install in UEFI mode, you need to install Windows 8 x64 & Windows 7 x64 in Legacy mode.

From Toshiba Support site.

How to enable CSM for a Toshiba.(Satellite Pro C870, Satellite Pro L830, Satellite Pro C850, Satellite Pro R950, Portege R930, Portege Z930)

Toshiba said:

To downgrade from a installed Windows 8 OS to a Windows 7 OS, using a Windows 7 recovery media, follow these steps:

1) Boot unit and press F2 to get into BIOS

2) Go to "Security" tab and disable "Safe Boot"

3) Go to "Advanced" tab, select "System Configuration" then change boot mode from "UEFI" to "CSM"

4) Press F10 to save changes and exit.

5) Boot unit from recovery media (Press F12 on bootup to boot from USB or DVD media)

theog :
so I should switch from "UEFI" to "CSM" .. then try to install windows 7 from my dvd... Will i be able to log to windows 8 again after this change ... or do i have to install it again ??.... i don't have windows 8 DVD .

Kaktussoft :
yes ,windows 8 works fine
i have tried "Fast boot" disabled before .. didn't work .

i have seen this tutorial before

Esmeal said:

theog :
so I should switch from "UEFI" to "CSM" .. then try to install windows 7 from my dvd... Will i be able to log to windows 8 again after this change ... or do i have to install it again ??.... i don't have windows 8 DVD .

NO.
Windows 8 x64 & Windows 7 x64 both need to be install in Legacy mode.

theog :
i read this
Create a Packard Bell Factory Default Backup in Windows 8
is a recovery media like that enough for re-installation of windows 8 ??....

will i lose the data on the third partition(the one that i won't install any windows on )??

Does make a difference which one to install first ??

sorry for the the many questions and thanks :)