If you have any peripheral devices attached to your laptop, even an SD card in the Card Reader, remove them and restart. If the screen remains black, you're better off contacting your retailer to see if you can exchange your defective laptop for a new one or get a complete refund.
If you hook the laptop up to an external monitor or HDTV and video displays on the external monitor, but not on the laptop display, it's likely the LVDS cable is poorly-onnected or defective. If both laptop display and external monitor fail to display video, the problem is likely the VGA.
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT