Very Slow boot up Windows 2000 machine

Hi,
I have a client who has a Windows 2000 machine that started having problems about a month ago. During the boot up process it take the machine about 10/12 minutes to boot up. It does eventually boot up and connect to the network. The only thing that has changed is they changed the monitor. We have changed it back to the other monitor, did not help. I have deleted the monitor and let the system refind it, did not help. I have replaced the network card, did not help.

Everything works fine after it boots up with no problems. It take about 2 minutes to go into My Computer, 2 minutes to go into Network Places.

Any ideas on what could be causing this boot up slowdown.
TIA
Robert Payne