Hello Adikbsw,

Please refer the article on performing a Clean Re-installation of Windows 8. Once the Operating system is re-installed, please ensure to install the drivers in the correct order. It is very important for the computer to function properly. 

**Note: Please ensure to back up all the data from your computer before re-installing windows as it would erase everything from your computer.

Please write back for further questions.

Sorry SIr, ive already read all of it, but when i pres F12 there are only 3 options

1) Setup

2) DIagnostic

3) Change boot option

That's all

ANd i can't backup anything, because i can't turn on the laptop, that why Dell sent me this REcovery SYstem disk

Sorry SIr, ive already read all of it, but when i pres F12 there are only 3 options

1) Setup

2) DIagnostic

3) Change boot option

That's all

ANd i can't backup anything, because i can't turn on the laptop, that why Dell sent me this REcovery SYstem disk

Select the third option--change boot option. Then choose the cd-dvd drive that has the install disk.

NO, the third option only givin me :

1) Legacy boot mode,secure boot off

2) UEFI Boot Mode, secure boot off

Turn Secure Boot Off, this should give you the options to boot from USB or DVD.

No, it doesnt give me any of these options. Allthe same .   Please could smbdy from dell support community answer me??!!

Disable it in the BIOS setup and also disable UEFI if needed. See here page 370:

http://en.community.dell.com/support-forums/software-os/f/3524/t/19480753.aspx