keep dropping server connection

[Rwhunt99]

workstation using win 7 is logged on to a domain, works fine, however; occasionally, when working the workstation loses the server and can no longer see it in the network panel. She has to reboot and then sees it fine.
I have changed network cable to the wall outlet, I have installed a discrete lan card with no difference, I have been able to ping the server from workstation, I have been able to ping from server. Problem is this is an intermittent problem and I am pulling my hair out trying to figure out what is going on. This is a new HP that worked fine in a different office, but acts up at this location, none of the other computers are having any problems. I have tracked through to the netgear switch and tried switching connections on the switch but doesn't seem to have any affect on the issues. got any ideas?