Spyder IDE is a complex but usually stable Python program. A problem symptom is Spyder not getting past the splash logo or not even showing the splash logo.

To totally reset Spyder (erasing all user preferences for Spyder), type in Terminal / Command Prompt:

spyder --reset

Normally, that fixes Spyder. To diagnose further, start Spyder from Terminal instead of OS Start menu, it might give some hints.