How do I lock the video resolution?

I have four PC'c connected to a KVM switch which in turn is connected
to an WXGA monitor with a resolution of 1680x1050. When one of the
PC's is rebooted or accessed via remote desktop it queries the
monitor via DDC to determine the preferred resolution. The KVM does not
intercept and respond to this interrogation so unless the switch is set
to connect the monitor to the rebooting PC then the PC will receive no
answer to the DDC query and will default to a 800x600 resolution. What
I need is a registry setting to disable the DDC protocol and hard code
a resolution of 1680x1050. Anyone know how?

Alan