We are having  novell 4.11 server. due to hard disk problem we have  replaced scsi  hard disk. old hdd is  makeing lot  of  noise otherwise  working ok. now with new hdd  windows xp  machine get disconnected after some time. xp machine  is  having novell  client.  it's works fine with  old  hdd novell. and  rest  10 desktop having bootrom.  we have copied  net$dos.sys from old server as it is. with attrib sh-r-w. when we copying old data from xp desktop  to new novell  server. utilization of server goes to 60 % during this diskless node stop after vlm...and gives seek error....please  help  me..  

Windows firewall is probably blocking the watchdog packets.

BTW if a hard disk is making noise, failure is imminent.  Noise means friction.