Automatic enable network card

Open the properties for your ethernet card in the Device Manager, select the tab that provides driver details and copy the driver name.

For Example, mine is >> dm9pci5.sys (for a CNet card).

Now run regedit and navigate to the following key >>

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

Do a "Find" for the driver name for your card.

In the right pane where this is found you will see a "start" type -- this is "manual" by default (at least it is for mine).

Try either setting it to "automatic", or "boot".

Change Value data to the wanted state:
0 = Boot
1 = System
2 = Automatic
3 = Manual
4 = Disabled