how do I increase the memory allocation for windows 7 lan driver

I need to know how to increase the memory allocation for the lan driver on windows 7. I have been having issues with these Windows 7 Ultimate pc's losing the network shares constantly. After doing some research found that others were having the same issues and no one was having any success except one person that increased the memory allocation for the lan driver. The only problem was that they failed to say how they actuall did this. It seems to be an issue that after awhile the windows 7 computer will stop responding to requests from the 2003 server and a reboot would fix. This one person increased the memory allocation for the lan driver and his problems went away. Can anyone tell me how this is done. I would like to try because none of the conventional ways listed in the knowledge base has helped. Please help me if possible. This is getting urgent as my boss is getting rather upset with having to reboot his pc multiple times during the day.