What version did you update to? G74SX's need either the driver from the ASUS site, which isn't exactly an update since it's as old as Methuselah or you need to use a driver with a modified INF (install script). The Verde 280.26 WHQL ModINF in
Chastity's driver thread is good, or you can go to
LapTopVideo2Go and get something more current.
ALSO it might be a good idea if you used DriverSweeper, also linked in Chastity's thread, to clean up the nVidia drivers between uninstalling the old and installing the new. Read everything you can before doing this!!!!
Does this happen when running any particular program?
Good luck. Hope you solve your problem. Let us know.
😉