Exactly what to do would be in your computer’s manuals.

The Dell Inspiron’s is here: http://support.dell.com/support/edocs/systems/ins1150/en/F7573a01.pdf

Laptops are generally harder than desktops to reset as it sometimes puts them in a “manufacturing” mode, so to speak. There might not be an easy way to do the laptop’s BIOS.

If you still have a service ticket with Dell, try calling their support and perhaps the friendly Indian folk you get on the other end will know of a way to reset it without requiring anything too drastic.