Hi everybody, I got the same problem on a MacOS X.3.4 Server (on a blue G3). It appears after the "combo update 10.3.4" launched with "Admin server", the server had never finished to restart, it's stucked on the "blue screen of death" before the login popup. The only thing i can do, moving the cursor mouse on the damned blue (and blank) screen, all remote access are disable (ssh, admin server, remote desktop, etc...). However, all others services appears to be OK (or open), this server is a firewall, all the network traffic pass trough it but we got no problem exept this one. No more control of server... Damn!...
Being a PC/Mac-User, it's funny to deal again with "blue screen" ;)
Apple and The Blue Screen of Death, the Truth