Instead of shutting down - OS restarts

[wielkaradosc]

Helllo experienced users,
I am struggling with this irritating problem since installing Win 8 Pro. When I want to shut down system, it just restarts, comes back to Win and just then it is possible to close OS. What's more, sometimes the OS doesn't load and I all see is black screen.
I have tried several things following Win 8 moderators' advices, but it resulted in nothing. Maybe you could help me? Maybe the issue is motherboard since it is responsible for power? My MB is GA P35 DS4 - I am afraid that there are no drivers for Win 8 for this product, at least I wasn't able to find them.
Thank you for any tips!

[ex58]

First:
http://www.askvg.com/fix-windows-8-restart-and-shutdown-problems-by-disabling-hybrid-shutdown-feature/

Second (LAN Driver):

Anyone that has problems with this issue can use the power.cfg command to help determine the problem. Run command prompt with Admin privileges. Then powercfg /lastwake That should tell you the most recent thing to have woken your pc.

I recently has this problem and was able to determine that my Realtek network drivers (which I just updated) were causing the issue. In the event that is your issue as well, you can disable "Wake on magic packet" on your network adapter. That fixed my restart instead of shutdown issue.

Another powercfg command for more details is the powercfg /energy Thatll create a detailed report you can view.

or Disable  'Wake on LAN' in the BIOS.

[wielkaradosc]

Thank you, sir, it did work.