Cracked Laptop Screen and External Monitor

Hello, I need help with this situation please.

I am hooking up my cracked screen Toshiba Satellite L305D-S5928 to a Dell external monitor and on monday it was working perfectly then i moved it a bit to the right then the screen died and went to the "Check Signal Cable" and it didn't fall out but now i can't seem to get it to work again.. i've checked the cable prongs and none of them are bent or broken off and i don't know whats wrong. And just so you know the only time i see the screen and everything would be at start up like, and then when it gets to logging in it goes to check signal cable so..

I'd greatly appreciate it if you could help me.