Edit: solved. Sorry guys, it was something silly. Instead of clicking shutdown on windows I just hard pressed the off button for some seconds on the laptop. So I booted back on windows and let it shutdown normally and then Debian was able to boot again. Hehe...
Boot from a live disc/usb, check the kernel logs. That should at least tell you where the boot process got stuck, what to do about it depends on what exactly broke.
Sometimes I write poetrule (lemmy.blahaj.zone)
Help me pls, Debian 12 is stuck at boot forever after using Windows on dual boot
Edit: solved. Sorry guys, it was something silly. Instead of clicking shutdown on windows I just hard pressed the off button for some seconds on the laptop. So I booted back on windows and let it shutdown normally and then Debian was able to boot again. Hehe...