Random Disconnect's

[Need Help]Random Disconnect's (All details included)

Description:
Hello guys , for the past 3 weeks im getting random disconnects at random times and i cant really understand what is causing them or how to fix them.

Things ive already tried:

- Contactmy ISP , check the line , replace their modem.
- Disconnected my own router from ISP's modem.
- Connect my computer directly through cable to the ISP's modem.
- Reinstall & update ethernet drivers.
- New ethernet controller card.
- Format & reinstall of windows 8.1
- Disable IPv6
- Disable automatic sleep of ethernet for saving power
- Put my physical address on network - properties - advanced.
- Switched both my modem and windows DNS servers to google.
- Ping my router when dc'd. (No ms , no packet loss)
- Tried cmd commands such as : DNS Flush , DNS Reset , ipconfig /reset , ipconfig/renew
- When i get dc's i used the windows troubleshoot and i got the "DNS Server Not Responding Error"

When i get dc'd from my computer the icon on taskbar that shows the status of the internet connection remains the same (connected). I just cant browse any website (getting stuck at Resolving server..) and im getting dropped out from everything. (skype , games etc)
I check the network with 2 computers at a time and my other windows 7 doesnt have any problems while my windows 8 is getting disconnected.

I had no problem before this , with windows 8.1 and i dont really want to go back to 7. If anyone can help please post. Thanks.

According to the Asus site there is a recent bios update that is supposed to help with system stability.

ASUSTeK Computer Inc. -Support- Drivers and Download P8H61-M LX3 PLUS R2.0

Have you tried updating the firmware on your router?

im back to windows seven just to ensure that this is caused with windows 8 only.
So far i got dc'd on windows 7 aswell , while downloading the windows 7 updates and drivers , but since my ethernet didnt have the drivers ill test some more to see if i get dc'd again.

No i haven't tried updating the bios and that might be actually a good idea. Ill try that.
I cannot update the firmware of the modem since its not mine ("provided by ISP") and the firmware update options are not available to customers. But i got the modem replaced even though it had no problems with a brand new one , and didn't have any problems with it in the past so i doubt its that.

i've rolled back to windows 7 ,ive updated the bios to the latest and still getting those random dc's...
Any more ideas?