You can't change resolution on a laptop. Or rather all LCDs. LCDs have what we call a Native Resolution that can't be changed. So while you can change this on Windows, it's not really changing the display resolution so to keep folk from calling support some systems just push it back to native resolution.
With that basic out of the way I see folk have discussed this before. Read from https://www.google.com/search?as_q=vista+resolution+keeps+changing
why is it that if I change my monitor resolution setting, it always goes back to default after reboot? I have to change it everytime start the laptop. I run a Sony Vaio with Windows Vista