The last version of the drivers are: 18.8.1 (2014-1-13). Did you already try those? (sometimes the DZ68BC download page doesn't list the latest drivers).
With Windows 7 I had also some issues in the past that the NIC wasn't correctly detected at startup. I am now on windows 8.1 and haven't seen that problem again.
You can try to disable some of the "power options" and wake up options. I had to disable "wake on pattern match" to prevent that my system wakes up to many times.
Windows 7 has also build in drivers, you can check if these work better. Most of the Intel driver "improvements" are mostly intended for server systems anyway.