Starting yesterday, some of the Windows XP machines in our environment have been dropping off the network seemingly at random. The only thing that fixes it is either rebooting or renewing the IP address (even though it will get the same address it will suddenly work). There are no errors showing up in the event logs of the machines and I ran a DCDiag on the domain controllers and everything checks out. We have also ran a few AV and Spyware scans on some of the machines and can't find anything.
Anyone have ideas on other things to check or what could be causing it?