Even though Windows 9x/Me may present you with a prompt to enter a username and password, you likely know that...
this can be easily bypassed. If the machine belongs to a network with a Windows NT/2000 domain, you can force Windows 9x to require proper authentication with the network in order to logon. It's a simple registry tweak as follows:
Windows 9x will now require proper authentication with the network in order to logon.