Difficulties with TCP/IP setting

I am running a small network for a charitable group. I was called in theother day as no one could hit the internet. I found that all of the TCP/IP settings had been reset to find automatically whereas they have to be manually set to find the modem. Default will not work. Is there aanyway that these settings could have been chnaged other than by someoene with administrative usaged on the network. Or could these have been reset automatically by any means.
I’ve changed all user priveleges to unlimited to try to resolve the situation. I had hoped to leave the team with admin priveleges but looks as if they canb’t be trusted and was hoping someone could throw some light on the situation.

Regards

Nicho
http://www.carewerx.com
Brisbane