Why does my Z turn back on after sleep mode

After I put my laptop on sleep mode and shut the lid down, I always see the computer turn back on automatically after only a few minutes (I can hear the laptop working and the light turns green, although the monitor remains off).

Why is this so? The laptop also seems to turn off after a while it is turned back on from sleep mode.

P.S. I also notice my Z having a particular video error at times. That is, sometime, the laptop monitor turns black for a few seconds, turns back on at the highest brightness setting, and a error message pops up saying something about how it was unable to find a driver. Why does this problem occur and is there a fix?

Overall, my Z is worth $2000 and is less than a week old, yet I'm having trouble accepting that I got what I paid for. The small errors are very annoying - I was expecting near perfection for that price.

 

the default setting is that both hibernation and sleep modes are set. so your laptop goes to sleep when you close the lid, but then the hibernation timer kicks in, and wakes your computer first, and attempts to hibernate. It can't go to hibernate directly from sleep mode.

Go into power settings and either disable hibernation, or set the timer to a larger value.

 

Go to control panel, performance advanced tools. u should see an exclamation point with a fix. if not u need to reinstall your nvidia drivers. i also have had this problem and reinstalled the video drivers available from esupport.sony.com

 

There's also an issue that sounds very similar to this that the new BIOS update is suspposed to fix.