Windows 7 x64 - network/internet not detected

I'm running Windows 7 Pro x64.
About 1 out of every 3 boots I get a problem where my network adapter does
not get assigned an IP address through DHCP. The network diagnostics says
there may be an issue with the driver or with the cable itself.
I'm using an Asus Striker Extreme motherboard which has two Nvidia NForce
gigabit ethernet adapters.
The switches and cables are fine. I can't find a way to do an adapter reset,
so I re-boot, then it works. A status of the adapter shows it is connected at
1Gb speed and the switches confirm that.
Is this a known problem and is there anything I can do about it. I'm using
the latest updates and certified drivers.
Thanks for any tips.

Try assigning a static IP address to your network adapter if it is not
imperative having a dynamic one.
If you still have the issue, or cannot go the "static" way, open an elevated
command prompt window.
Type "ipconfig /release" and later on "ipconfig /renew".
That should reset the network adapter and force an ip assignment.

From that elevated command prompt, type ncpa.cpl. Now, click on the adapter
and then click on the "disable" button. Wait a few seconds, click on the
Enable button. This is goes a step further than releasing and renewing.

I've only just read your reply after finding what I
hope is a solution earlier today.
I noticed that an IPCONFIG /ALL did not list the adapter. It listed all the
others. It was as if the adapter was not seen by the Windows network stack,
yet it was there present in device manager.
I've read alot of postings of people having this problem - it seems it's
quite a common problem for those users with motherboards using Nvidia nForce
ethernet adapters and some Realtek ones. Mine uses the nForce 680sli chipset.
The problem seems to be driver related and the recommendation I found was to
download the correct driver set for nForce 680sli enabled motherboards direct
from the Nvida website, were you can specify Windows 7 and x64 criteria to
find the right driver. Anyway, it's installed and working. I'll post at the
end of the week to let the group know if it's reliable.

Thanks for your suggestion. The problem I reported, which appeared to be
fixed by using a newer driver from Nvidia, has returned. It happens less
frequently - just once in one week.

I tried the elevated ncpa.cpl. I was able to disable the adapter, but when I
re-enabled it my PC hung for a minute, then blue screened with a STOP x07 in
nvlddmkm.sys. It looks as if there are still problems with Nvidia's drivers.

I re-booted the PC, and it was fine after.

This problem kept affecting my PC about 1 or 2 times a week, so I dug a bit
further.
I found some information on the Nvidia forums where someone has found a
workaround which is to disable 'receive side scaling' on your nvidia
ethernet adapter settings. This only applies to Win7 x64 using Nvidia
chipsets as I've described earlier. So far it's working for me. Hopefully
Nvidia will address this problem with an updated driver.