I have bough a new motherboard since i thought this was my MB making the problem.. feel kinda silly now and maybe i send it back instead..

I googled to this site and then tried all the hardware tricks listed here and nothing worked.

After that, I bought the Win 8 upgrade and installed it and all the drivers were there and everything worked fine.

After that, I reinstalled the Win 7 .iso on a separate partition, and again, there was no Realtek driver installed in Win 7.

So, in my case, I’m now sure that my missing Realtek Ethernet driver was a software problem and not a hardware problem.

Fortunately, I’m always able to bring the network adapter back by shutting down and unplugging the power cord for a couple of minutes; no RAM or battery removal required. Unfortunately, changing the power management setting does not resolve the issue, and the network adapter disappears every single time I shut down the computer. 

Here’s what I have to do:

1. Start the computer — see that network adapter is missing from Device Manager.

2. Shut down the computer, disconnect the power cable for a couple of minutes.

3. Boot. Network adapter is back in Device Manager. It say’s it’s operating normally, but it isn’t. When I try to enable it, it then says it can’t be started (Code 10).

4. Uninstall network adapter.

5. Shut down. Unplug power cord for a couple of minutes.

6. Restart. System reinstalls network adapter. 

Most of the time this gets me back on the network. Sometimes I have to boot once more.This happens every single time I power down the computer.

I’ve installed the latest driver from Biostar. I’ve fussed with the driver settings. I’ve checked the BIOS settings. I have not flashed my BIOS. The fact that it’s fine in everything but Win 7 makes me feel like it’s not a BIOS issue.

I just had this issue with a DELL INSP n4110- Win 7 home 64 bit- Asus MB, 6gb RAM, 650 GB  hd. Phoenix-tianos build BIOS.SPENT 3 DAYS KNOWING THIS WAS NOT A HARDWARE FAILURE…DO NOT BUY A NEW MB OR NIC CARD UNTIL YOU HAVE TRIED ALL THE STEPS MENTIONED ABOVE OR HAVE A PROFESSIONAL DO IT FOR YOU..DONT GET STIFFED EITHER..IT MOST LIKELY IS (in some cases) JUST A BIOS ISSUE…

Ok so if you have
* taken out the battery (cmos too if you have one.)
*you have taken out the RAM for an hour (or more) *.
*have reformatted your system
*tried “flashing ” the BIOS
*unistalling/reinstalling adptrs
*diagnosed ram
*check power state settings
*updated drivers thru dev mgr
and you still are unable to get the system to detect a network adptr AND you recieve a message “if your pc is in deep sleep, please plug the cable in”…..

 I did notice how my computer got into deep sleep mode. I made a BIOS  settings change by disabling an HD Password that was set by my newphew. Upon exit…i must have hit “load set up defaults” thats when i discovered the loss of my nic components and was unable to find a netwrok adptr. i also got the
“your computer is in deep sleep mode..please plug in the cable ….”   I KNEW THIS WAS  NOT A HARDWARE ISSUE…I TOOK THIS COMPUTER APART SEVERAL TIMES.  i ran MEM-TEST to check for RAM errors, I ran HD Tune-pro to see if i had issues with the HD. i  clean installed windows multiple times and also flashed my BIOS. I knew all the more AFTER I DID BUY A NEW NIC CARD ..it still wasnt found ….
 TRY THIS*****

Go into your BIOS   (to those that dont know turn on pc/or restart and immendiatley key “f2″ go to adavnced/. ( every build is diff…try to use similar paths)
go to each tab and hit “load defualts”
then when you go to exit the bios…MAKE SURE YOU HIT “Load set up defualts” (if it says that or whatever” regardless of its settings” go back into windows (let pc restart)……see if a baloon at bottom right hand portion of your screen says “loading/installing/found new hardware” if you see this…we solved your issue.
 
now if that did nt do it….ONCE MORE…go back into the BIOS…find where the settings for either “intergrated nic” or “on-board LAN” ENSURE THEY ARE “ENABLED”. That should do it …EXIT AND SAVE CHANGES…LET pc reboot…it should have worked. that is all the info i can offer. hope it helps.

Open Network Controller properties by:
Double-click Network adapters to expand itDouble-click the Realtek Network Controller

Turn off Deep Sleep mode by:
Choose the Power Management tab
Untick “Allow the computer to turn off this device to save power”

THNX