Alright guys, here´s the problem: We´ve set up two DHCP servers in the network. The first, located in the PDC, has a global scope. The second is a local scope located in a BDC. After everything was up and running, we started passing machines from static IPs to DHCP. On 90% of the computers, this will be done flawlessly. But on the remaining computers, something strange happens: they randomly lose their ability to logon. That is, after a few restarts they cannot find the DCs anymore. Since this was all provoked by the static-to-DHCP change, we focused on this during the first weeks, but with no luck. I have a few Win98SE workstations installed *from scratch* that will also present these symptoms. On 50% of the time, deleting the DHCP lease for the troubled machine and rebooting it will let it logon again. On the other 50%, a reboot of the PDC was needed (at least that fixed the problem). However, I´ve found today that none of these tasks are needed. I can logon again on a Win98SE machine by simply rebooting it into Safe Mode and then back into normal mode. What the heck is going on, I don´t know. It seems it´s a Win98 bug, but if any admins know what else could it be, I´d be happy to read about that. Thanks a lot Andrés