I would suggest you to follow the below mentioned steps in order:
· Remove the external devices and check if any of them is causing the Blue screen.
· If you are able to boot then perform a clean boot of windows by disabling 3rd party services.
· Rollback any recently installed drivers / software.
· Check if you are able to boot into safe mode. If you are not able to boot into safe mode, try system restore from windows recovery options.
· If the issue still persists, then try running the Hardware Diagnostics. In order to run Dell Diagnostics, follow the mentioned steps: Restart your computer. When the DELL™ logo appears, tap <F12> immediately. In the boot device list, highlight Boot to Utility Partition and press <Enter>. Under Dell Diagnostics Main Menu (see Dell Diagnostics Main Menu), select the extended test. If you get any error code, make a note of the error code.
Share your comments if it solved your problem.