I will try and take a stab at this.
It very important to phrase you words carefully.
When you speak in terms of native resolution of 1680x1050, This tells someone that this the maximum resolution that your monitor is capable of displaying, and not what your actually desktop resolution. So don’t use the word native and speak in terms of resolution.
What OS are you using and what service pack?
What Video card are you using and have you updated the drivers for it?
Please give some more details about your system, because there has been numerous reports in which desktop resolutions are not staying at the selected setting when coming out of sleep mode. The cases in which was the cause have varied.