C'mon @halimsideek - Pull Yourself Together!!! :reaches through monitor, grabs shoulders and shakes @halimsideek vigorously...
1) Others have reported long black screens (as much as 3 minutes) when booting with recent NVIDIA driver versions. Try the latest 304.48 beta if you wish, but boot into Windows Safe Mode and do a clean install (choose "Custom Install" and check the "Clean Install" checkbox. If this fails to resolve your black screen issues and you can't run 120 Hz refresh rate (I am assuming you are selecting 120 Hz from Windows Screen Resolution dialog and NOT from NVIDIA Control Panel as a CUSTOM resolution - if you are, let us know immediately), backrev to the original NVIDIA version that shipped with your G74 (I think it's something like 268.37).
If you STILL can't run 120 Hz, perform an ASUS Factory Recovery - press F9 at the ASUS splash screen and choose to restore Windows to the 1st partition. Back up any important files on that partition because it will get completely overwritten. If this fails to allow 120 Hz, contact your retailer and see if you can exchange your laptop for a new unit.
2) If you do resolve you video issues, determine if you have a Sentelic touchpad by looking in Device Manager under "Mice and other pointing devices". If so, uninstall your current touchpad driver (if more recent than 9.1.7.7) from "Control Panel - Uninstall a program", REBOOT into Safe Mode, and install Sentelic version 9.1.7.7. REBOOT, and disable the touchpad by pressing Fn-F9, then attach your mouse.
If you have a Synaptics touchpad, install the latest Synaptics driver version and disable the touchpad with Fn-F9. It is important that the touchpad be disabled when you use a Mouse. The earlier version Sentelic drivers would allow the touchpad to re-enable when using a Mouse, causing problems.
The key thing you want to determine is if the laptop has issues you cannot easily resolve while in a stock configuration. If that is the case, you need to exchange your laptop for a new unit or return it for a refund. Don"t let anyone talk you into a warranty repair if you are still within your retailer's exchange/return period. Once you accept warranty repair, the laptop and its problems are YOUR problems, and you must wait without a laptop while yours is repaired. Of course, if you are already beyond the exchange/return period, warranty repair will be your most cost-effective choice.
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT