Perform an ASUS Factory Restore by pressing F9 at the ASUS splash screen. Choose to "Recover Windows to the 1st Partition". This will overwrite your C: drive, so backup any important files you've stored there first. If the ASUS Factory Restore fails to resolve your issues, I recommend taking advantage of your retailer's exchange/return policy and exchange your defective G75 for a new one.
Don't let anyone talk you into an RMA for ASUS Warranty Repair. Let the retailer and ASUS sort out the defective laptop. When you purchase a new laptop, it should work correctly right out of the box.
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT