Installed Windows 8 not happy

I did install windows8 on my laptop, but not happy with it want to reinstal Windows7 but cant enter BIOS.
Any ideas what has happened...

We need you to fill out your specs so we can help you c:
You can look up the model of your computer and search up what button makes it go into the BIOS when it boots up if you are not feeling like posting your specs.

Depending on your make and model,

Pressing DEL when the computer boots up, try F12 or F8 or F9

As has been said without your make and model, it makes it hard for us to help you fully.

You may have to turn fast startup off to make it easier to get in.
Fast Startup - Turn On or Off in Windows 8

Everything you need including the latest official installer is here to Clean Reinstall - Factory OEM Windows 7.

If you have an EFI BIOS you'll need to either enable Legacy BIOS or install to UEFI (Unified Extensible Firmware Interface) - Install Windows 7 with - Windows 7 Forums.

What happens when you tap the key given for BIOS setup? You may need to manually Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS,

You can also use a self-booting disk like your HD Diagnostic CD or Partition Wizard to wipe the HD which will force the the Win7 installer to boot to reinstall. You can rescue files using self-booting Paragon Rescue Kit Free Edition 11.0 Free

Sorry to be so long in answering, My laptop specs:-
Fujitsu SiemensEsprimo model V5535
Windows8
Bios Phoenix V1.03 11/30/07
1.60GB Harddrive
1790mb memory

Have now entered the Bios, selected start from CD, but it still loads windows8 not install windows7....

In addition to the other steps I gave you earlier, on a Win8 PC you'll also need to disable Secure Boot in BIOS setup to install Win7: Downgrade Windows 8 to Windows 7

If you're not willing to mess with UEFI BIOS yet then you can more easily install Win7 normally to an MBR disk using Bypass UEFI to Install WIn7

To help decide and understand UEFI BIOS better watch this video: Technical Note: UEFI BIOS vs. Legacy BIOS - YouTube