This is a new problem......... I can't find any solution anywhere. I'm looking for a solution for my boss at work.

What I know is that he has a Netcom 311 gigabit card and he tries to transfer large data files between two of his computers using LAN. When he does this the computer restarts, it's pretty annoying any suggestions?

Might be easier for him to simply buy a USB to USB cable and get him to transfer the data that way. they only cost about $10

That's interesting - is there a bluescreen that flashes briefly befoer the reboot? If so it could be as simple as updating a driver. Have you checked for a driver update for the card from the vendor? Does the user have plenty of RAM? Try Start-->Run and type %tmp% and click "ok"...I have seen Windows do crazy stuff when the temp directory is set to a non-existent directory. Try logging on as a different user and do the copy. Also, if he has multiple RAM chips, take one out and test or swap in a known good one. Check the page file and make sure it's correct for the amount of RAM installed (generally 1.5xRAM). Run/schedule chkdsk against the drive to be sure there's no errors perhaps on the area of the drive Windows pages to. Good luck!