It's not possible for a wrong screen to become damaged, or to cause damage, as the cables just send picture signals on all standard LVDS cables (that's the flat type, ribbon connections that fit in the rear of the screen).
The actual voltage cables only go through the inverter circuit which is a totally separate part of the screen setup.
You mentioned that the laptop is now staying in sleep mode, but how do you know ? Some have the power LED flash on/off slowly so i'm assuming that is what you mean?
To know if the laptop is working when turned on, press the CAPS LOCk key a few times after turning on. The CAPS LED will flash if it's running but you just cannot see the display. If it has another type of fault, it won't change.
It's very easy to break the ribbon cables to screens even if they still look perfect, but the most common thing is that it's damaged the flat socket on the screen itself :( They often get pushed in too hard or at an angle and cause tiny faults, and ive even found ones where the cables been pushed in upside-down as they can fit either way round.
You can also test the laptop using another screen if available, any size will do as long as it has the same connection for the ribbon, and for the backlight power wires (usually 1 or 2 white or grey plugs, but only using one is fine, it just means you only get one light at one side of the screen - fine for testing).