Monitor and Internet Problem

[marcmarteleira]

The internet on one of my computers is not working properly, It is going from Modem > Router > 5 Computers, it shows its connected and everything but when we try to load sites on it, it doesnt load them, it says it Couldnt Connect.

My monitor keeps flashing on and off and shows no signal or anything, my computer is on and the screen STAYS black and just keeps flashing on > off > on > off over and over, even when the computer is off, anyone know whats wrong with it?

 

[marcmarteleira]

Oops, I posted this second post by accident, edited. sorry.

 

[^Mike^]

Weird, is your monitor cable securely attached to the back of the computer?