Is the bios doesn't see it and the 500GB does get seen that sounds like the bios has an issue with the large drive. Or you've tripped over the rare issue of SATA 1,2,3 compatibility issues. Only Dell may know this one.
However I've encounter too many folk that can't partition and format a drive today. Good luck.
I have an XPS M1730 running windows 7 64bit OS. It has 8gb ram memory, 1000gb hard drive, a new wifi card, and it has a weird problem. I recently wanted to upgrade a few things in this laptop, as it was about 4 years old. New wifi card and new hard drive. New wifi card works great. Intel n6300. when I went to put in the new hard drive, issues started to happen. This is not the first time I have put a new hard drive in this computer. I had previously upgraded to a 500gb hard drive, no problem. That was about a year ago. it has the ability to operate dual hard drives at the same time with a ribbon connecter running to both, which are stacked on top of each other in the hard drive basket underneath the laptop. One is marked with a 0, the other with a 1. I have operated two hard drives at the same time before using this same computer with no issues. My understanding is that the 0 slot is the main hard drive slot in use from the factory, with the 1 being used for an additional hard drive if desired. This was how I had been using it. Now for some reason, when I tried to install the new hard drive, the computer wouldn't "see" it in slot 0, but it would see it and operate from it in slot 1. I tried changing out the ribbon, and it won't recognize any hard drive with the new ribbon. Tried finding a solution in bios, that didn't work. finally installed a new motherboard, and encountered the same problem. The laptop still will only recognize / see one hard drive, and only in slot 1, and only using the original dual drive ribbon, not the new one, even with a new motherboard! What am I missing here?