I have a D800 that does the same sort of thing.  I hope you find an answer as I have just replaced the motherboard, video card and updated all the drivers without any success.  This is very annoying.

 

Russ

I 've just bought a D800, and I'm having the same problem. Did you solve it?.

I'm having the exact same problem with my C840. Every time I close the lid or reboot the screen shrinks. Also, I'm able to reset it using the resolution settings on the Display Control Panel. When I change the resolution settings, the display goes back to the full size of the LCD and I can then set the resolution back to my preferred setting. I've also noticed that this isn't a problem when my laptop is docked and I'm using an external monitor. However, even though I'm running XP too, I can't say that it had anything to do with standby. I'm not saying it didn't, I just have no recollection of the events being related. Please let me know the status of your progress on this problem. Thanks!

I finally solved my problem, and the problem was: a third party software (pc-anywhere), I uninstalled it, and 'voila' , problem disappeared.