Cody, I know this is an older one.. but it seems you are in the same boat I was in... this was a problem with your video driver setting.
Here is the weird issue, Second Life uses Open GL vs Direct X. What I found out, is with this laptop you have "2 video processors", the nvidia and the onboard intel. What was happening to me, was the driver was not configured correctly to change to the "NVIDIA" graphics card vs the onboard. Once I updated the display driver (from the NVIDIA site, not the dell drivers, which as SOOOOO behind), I was able to configure SL and Firefox to use the right card. It was sooo good to get it to finally work.
The i7 Dell XPS 15 is WAY POWERFUL to use SL.. I get wonderful graphics and good frame speeds. I would recommend for you or anyone else on the NVIDIA cards to make sure the PC is usuing the NVIDIA and not the onboard graphics when using SL.
"Originally developed by Silicon Graphics in the early '90s, OpenGL® has become the most widely-used open graphics standard in the world.. NVIDIA supports OpenGL and a complete set of OpenGL extensions, designed to give you maximum performance on our GPUs. NVIDIA continues to support OpenGL as well through technical papers and our large set of examples on our NVIDIA Graphics SDK."
So the newer drivers should work fine... they do work well for me!