afaik, monitor are responsible to the
Turn Off Monitor (see picture) feature. i never had problems with my monitor. it is energy star compliant and it can be powered down by windows.
for the StandBy it may be BIOS and some other factors, but i dont know which.
@trminatr, yeah the BIOS shows APM enabled.
@Sephiroth, u asked my type computer. m8, shall we proceed with the next step? thanks! 