Insert the SD card. Turn on the Dell, and when the BIOS screen appears press F12.
You will then get a list of devices to boot from. Select the SD card and continue.
- Enter BIOS (probably F10) and change the boot order so
that the SD card is the first device.
- Install Grub2 bootloader onto the hard drive. It's quite capable of
booting off the SD card. This might be the best solution as you will
always get the boot list (Windows or Ubuntu) and will not have to
fiddle with BIOS or function keys. To do this, install Ubuntu onto
the SD card but make sure you install Grub to the first hard drive
(advanced partitioner) in the setup programme.
Be very careful when using the advanced partitioner. The hard drive will most likely be /dev/sda while the SD card may be /dev/sdb or something else if there is a separate card reader in the machine as well.