[NAME] hameed , BIOS or system utility is designed to control how the hardware will perform.  Making change to match with hardware environment will get optimal performance.  Some changes do affected system behavior and sometimes causing BSOD or unwanted performance.  A clean install will help to fix those issues.  If you prefer to start fresh and perform a clean install, set system utility to the option you would like and follow the process here: First method is using official Dell OS recovery tool which can be used to create a bootable USB flash drive to install the OS. You will need to use another computer to download the OS and follow the steps below. This is needed to install and download Windows: Service Tag of the Dell PC on which you want to install Microsoft Windows or Linux Blank USB flash drive with at least 16GB of free space Microsoft .Net Framework 4.5.2 or higher Administrator user rights and at least 16GB of available storage space to download the Dell ISO recovery imageFor creating a boot-able windows USB flash drive please follow these steps: 1. Download and install the Dell OS Recovery Tool.2. Launch the Dell OS Recovery Tool, switch it to the advanced recovery tool and enter the Service Tag of the PC that needs its operating system reinstalled (Select the Re-install Windows manually).3. Select the operating system image you'd like to install, and the OS Recovery Tool will build your bootable USB recovery drive.4. Install the operating system using the newly created USB recovery drive. This will remove all data and software from your PC's hard drive and restore the factory-installed operating system. You can download the Dell OS Recovery Tool by following this link: [URL] After creating the USB boot-able drive: 1. Connect the USB recovery media that you created to the Dell PC where you want to install Microsoft Windows. 2. Restart the PC and when the Dell logo appears, tap F12 key until you see Preparing one time boot menu in the top-right corner of the screen. 3. On the boot menu, select the USB drive and press Enter. 4. On the Choose an option screen, click Troubleshoot, and then click Recover from a drive. Caution: This will erase all data on the target drive(s) 5. Follow the on-screen instructions to finish installing Microsoft Windows. The installation process will take some time and your PC may restart several times. For more detailed instructions, please follow this link: [URL] Second, more preferable method is to download Microsoft windows creation tool (win10, win11).  For preparation, you will need a blank USB drive at least 8GB of free space.  Back up all your data as the process of clean install will required formatting your drive, all data will be lost.  To create installation USB drive: 1. Launch the downloaded creation tool. 2. Select to create installation drive to use on another machine. To install windows, plug in your USB drive, boot up your machine and tap on F12, select USB drive under UEFI and it will start the installation process: 1. Follow prompt and select language and next 2. Select Custom install 3. Select each partition and delete, you should have left with unallocated space disc 4. Select the M.2 drive and choose next to let windows create partitions and the installation will start. When the installation complete, you will need to install chipset driver and intel MEI driver.  Connect to internet to reactivate windows and download all update.  Go to optional update, your drivers are also there. I hope this will help you as well as others.    
Hi Experts ! I have a dell 7710 laptop in legacy mode all boot sequence is available such as HD / USB storage / m.2 pcle ssd etc..  Bios system information also showing    2 slots  of m.2 pcle used and 1 slot of SSD Sata. but in uefi mode only the HD main is visible I need to boot operating system via m.2 pcle ssd and for some purpose USB storage also...  Secure boot is enabled  Uefi mode selected 
Dell 7710 uefi mode doesnt show usb /m.2 pcle in boot list