installing W7 pro on a inspiron 3542 laptop which already has W8 what do i need to know ?

There should be nothing you;d need to change in the BIOS.  And I'd hazard a guess that if Win8 is supported then Win7 should be fully and 100% with regards to the drivers.  To be safe though I'd preemptively download the networking drivers.. nic, wireless, etc.  That way once you've formatted and installed Win7 just in the off chance that Win7 does not contain the correct drivers you can install those to get it back online to get the remaining updates, etc.

I would assume that the Bios is UEFI and this can be problamatic if you are installing a win7 pro which does not have UEFI compatability. There may be settings in the bios which will allow a legacy install but that is not always the case. You can create a win7 UEFI compatible install on USB stick but can be an involved process.
http://www.eightforums.com/tutorials/15458-uefi-bootable-usb-flash-drive-create-windows.html
It may be easier to make win8 act like win7 rather than a total clean install unless the win 8 is trashed.There is a program called "classic shell" which gives you a start button and navigation through windows just like win7.
http://www.classicshell.net/

Hi Sparkmaker;
I really want to get rid of W8, and converting the English to French ( could not get the O/S in French at purchase and was not giving Dell more money for a license I already own)

Hi Ben Hart;

So if I do an install direct from the DVD ( bootable) W7 Pro 64 Bit I should have no issues ?
 I have downloaded the drivers and the Dell auto detect program.

Try this first.. boot off the DVD and in the boot device menu see if you have a UEFI selection.  Judging from this: http://technet.microsoft.com/en-us/library/dn336946.aspx Using a DVD, you need to boot the media in UEFI mode in order to use GPT by default.

Before you do this take a full backup of your system. Maybe you would want it back in future. After that clean up the drive by erasing it.
Then perform normal installation.
If the system you are going to install is Windows 7 64bit then it will install on UEFI as well.

ok I checked your recommendations guys thanks my issue is to get laptop to boot from DVD ?
From what I see and read I need to turn off UEFi in boot menu ( Dell bios) and it should boot from DVD then go back and reset BIOS for UEFI secure boot , correct ?

Not UEFI but Secure Boot option.

Ok now I get message stating cannot load w7 on partition 5 since it is a GPT,
other partitions are the Dell ESP DIAG Winrettools
should I just format partition 5 or the whole drive ?

Is the install DVD with 64bit OS? If yes then delete last partition and select this free space as target for installation.
If you have created the backup already then clear up the drive from partitions and perform clean install of OS.

First use the "Recovery" option in the control panel to create a factory recovery USB stick. This copies the recovery partition and a repair boot system to the stick, so you will need to make sure it is a little larger than the recovery partition (but not much larger as you don't want to waste space on the stick). When done lock the stick away. You will need it if you ever want to return to Windows 8.x, or if you want to sell the PC, as then you can sell it with the original OS. This is something that should always be one of the first things to do on any new PC.

By the way, you can install additional languages in Windows 8.x via the control panel, languages. So you don't really need to have a french version installed (although there can be some mixups in the Windows 8 crapps, but those aren't of any use anyway, so who cares).

You can only install a 64 bit version of Windows to a GPT disk. Are you trying to install a 64 bit or a 32 bit version?

I am pretty sure it is 64 bit but will check ISO is used
Thanks will make recovery back also

The first thing you need to do in the BIOS is disable Secure Boot.

That will let you boot from a DVD.

Then change the BIOS to Legacy mode.   Be sure the disk access mode is set to AHCI.  ... and then you can install Windows 7 very easily.

As long as the OS you want to install is 64bit it must install even if it is GPT drive.
Make sure the free space or partition you want to install the OS to is big enough for the OS.

You have some knowledgeable experts in rindi and garycase, I would take their advice on how to proceed. The creation of the recovery usb that rindi suggests should be the first thing you do as it will allow you to get back to where you have started from if this install blows up. Remember to check the box next to the "Copy the recovery partition from the PC to the recovery drive" if there is a recovery partition.

Here is a good link on making the recovery usb
http://windows.microsoft.com/en-CA/windows-8/create-usb-recovery-drive

and also - verify if there are drivers for Windows 7 for your system
what system is this?

Thank you all for your comments and suggestions, as for the recovery I made one ( windows recovery with copy of recovery partition of laptop)  and safeguarded the drive :-)

I will be doing the install today, based on your comments,  once done will advice status to you, then award points, once again thanks all.

Sorry for late follow up, I have ran into a problem with install, get message stating cannot install windows on drive dick 0 partition 5
Dell has partitioned the drive into 5
1 ESP system
2 DIASGD OEM
3 3 MSR
4 WINRETOOLS OEM
5 Principal

do I need to delete the drivers ?

sorry mean" do I need to delete the partitions"

The next section of that tutorial shows the method for prepping the hard drive for the win 7 install using Diskpart at the command prompt.
http://www.dell.com/support/article/us/en/19/SLN116104#Install-Windows-7

all the solutions proposed help make this transition to W7 very easy

worked great install all done , thank you very much all who posted here