I have just purchased a new computer (Asus Q500A) and I am having trouble understanding how to change any "monitor"/screen settings. On my previous computer, I did install the appropriate tool for my graphics card, but settings were never saved as defaults (I had to change them every time I logged in), so in the end I gave up and settled for dropping an xgamma (gamma was the most important value I wanted to change, anyway) setting in the startup commands.
I tried using the same method, and as I am logging in, the gamma changes to the setting I chose (0.7), but only for a very brief moment before returning to 1.
A.) Why is this happening?
B.) Is there a better way to set my gamma (and, preferably, other screen values) in 12.10?

Thanks.