XPS 8940, stuck on boot logo

Try a reset by disconnecting the battery and adapter then press and hold down the power button for 30 seconds then reconnect everything and try to boot. If that does not help, this forum post may offer some answers.

@PCHPC 

Take a look at these links, one should work for you:

https://www.dell.com/support/kbdoc/en-us/000132453/how-to-recover-the-bios-on-a-dell-computer-or-tablet

https://www.youtube.com/watch?v=WC24Np6H95I&ab_channel=DellSupport

https://www.partitionwizard.com/partitionmanager/bios-auto-recovery.html