Not able to change LAN properties to connect at work to server

When I am at work I need to change my TCP/IP protocol to be able to connect to our network at the office. My problem is after I make the changes to the properties and go to close my computer locks up and then I have to reboot to get it back to normal and then when I check the changes they have reverted back to the previous settings. The only way it seems that I can do this is to delete the device and reboot and let the computer find the device and then I am allowed to set the properties once. If I then want to chenge it I have to go thru the whole process again. can someone help?