Have you disabled the "Allow this Device to Power Down" feature in the configuration tab?

bad capacitors have been known to cause all kinds of strange problems with the 260 and 270's.

just a thought. if you haven't done so already, inspect the caps on the affected machine for swollen/bulging or leaking capacitors.

These don't seem to have the capacitor problem that the GX270's did. With having Dell come out and replace all the boards in almost 200 of those I know how those behave and look. That was one of the first things I check(ed.) I honestly wish they were blowing capacitors as Dell would replace the motherboards even though they are out of warrenty. I'm going to try the other suggestion and flashing the BIOS to a newer version, taking a long look at all of the network settings. Although we also had this issue last year when we were running Windows 2000 with a different image. Part of the problem in troubleshooting is that these machines are always in use and have to be where they are due to class size issues so they can't be in the workshop sitting here being experimented upon for long time periods. I really wanted to know if anyone else is experiencing the same or similiar issues so that the cause could be at least whittled down to two or three possibilities rather then a wide range.

Thanks for all the help.