|It all depends on if the password is set in the BIOS or by a 3rd party utility. Sounds like something that could be as simple as resetting the BIOS. Typically, this type of password is stored within the BIOS and by removing the CMOS battery on the motherboard for about 5 seconds it should cause the BIOS to forget user defined settings and default back to the original default configuration thus removing the password.|
If your computer is under warranty by Dell still, you shouldn't try this yourself since it would probably void the warranty. But if your system has a CMOS battery it would be located on the motherboard and looks like a large watch battery (silver about the size of a dime typically). Usually they are easily visible by just unscrewing the bottom access panel, but some are hidden behind other cards and are difficult to get to.
It could also be that the password is set via a specific utility and in that case it is not stored in BIOS and the above fix wouldn't help you.