There’s a specific Dell laptop reset procedure that requires you to open the case and disconnect the battery so you can then press and hold the power button to get it to discharge all residual power. It’s a pain.
I had to do this a couple of times with a Lenovo that sometimes locked up completely when it went to suspend - battery was highly inaccessible so it was a 30 minute tense process each time - firmware update eventually solved the problem. Not sure what the solution for this is - something like one of those paper clip reset holes?