In old versions of the driver there was an issue with DPMS and some GeForce Go models: when the LCD went into stand-by, suspend or off, it did not turn on again, no matter how much the user moved the mouse or touched the keyboard. This issue has been discussed in this thread
This problem has been fixed in version 8174. But now I am having it again on 9631!
Could other GeForce Go users running 9631 check what happens when the following command is run (as a regular user):
xset dpms force standby