|Have you tried pressing f 12 at boot to get a boot menu?|
Getting the bios password on a laptop is next to impossible, without proving ownership to Dell or taking the computer apart, partially reassembling and shorting the eprom. The eprom is about this big ( # ). If shorted incorrectly it can be toasted.
If computer is warranted by seller ask for password or money back.
Hope f12 works for you or seller has the password or a reputation to protect.