Blue Screen of Death issues are usually caused by two things: Bad memory, or corrupted kernel processes.
Keep in mind that most OS's (including Windows) operate in two modes. User Mode has all the user-level programs running, which include the desktop, any apps, and drivers for USB devices. Kernel Mode is all the operating system processes, things that are running in protected memory.
When a User Mode process crashes, the OS simply stops it and pops up a "Sorry, had to shut down MisBehavingProgram.exe". However, sometimes, if a memory chip fails or if a program is written badly and doesn't release memory it no longer needs, you'll get situations where something will try and grab protected memory. At that point, the OS blows the whistle, and EVERYTHING comes to a halt. This is when you see the blue screen.
If your OS is configured to "Halt" when this happens, that screen will stay up until an operator comes along and reboots the machine. However, many are configured to "Restart", which doesn't give anyone the opportunity to see what went wrong.
At this point, I would recommend going into the BIOS (F2) and setting it as "Fast Boot OFF". This disables the DELL splash screen, and instead enumerates memory and drivers as it boots. Then, when you reboot, watch the memory counter as the memory is tested. If it doesn't display the amount of RAM you have installed, then you've a bad memory DIMM and that's likely the cause.
Also, as the system reboots, you'll have more opportunities to invoke F8 (Safe Mode) once the system tests and initial device driver load are complete.