1) Does the ASUS splash screen appear on the attached external monitor, or on your laptop display if you removed the external monitor?
2) Does removing everything from all ports (including the card reader), unplugging the laptop, removing the battery, holding the Power On button down for 30 seconds, then plugging in just the power adapter and restarting, display any video on the laptop display?
3) Have you tried reseating your HDD?
4) If you spam F2 on startup, can you enter the BIOS with video displayed?
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT