Dell is not going to support a system that's more than a decade old, nor will it support an operating system it has never tested for functionality with your system.   Can you in fact make any changes to your system setup?  If not, it is possible the setup is locked with an administrative password -- have you owned the system from new or was it purchased used?   There is plenty of help out there for installing Linux on older systems.  One link is below.  The fact is that any support you might seek outside of that online will cost you, and you have a system that's worth a total of $50-150 depending on configuration, so you'll be spending upward of what the PC is worth just to get the OS installed. [URL]    
Hey, I wanted to install ubuntu on my xps L702x recently.  But i ran into issues as described in my post on the linustechtips forum[URL]#comment-15483175 I am just looking for some answers if there´s a way to install ubuntu on that machine or if its just impossible due to a bios lockdown.
Unable to install linux