Power up your system and press F2 at the Dell BIOS screen to enter the BIOS setup.

In the BIOS setup there should be a category called onboard devices, expand it. Go to SATA operation.

Note: The mouse/touchpad isn't present in the BIOs setup, you will have to use the keyboard arrow keys to move between the fields and enter to select a setting.

Switch the category from AHCI to ATA or ATA to AHCI as desired.

When finished, press esc and you will be prompted to save and exit or just exit. Select save and exit