I am checking a friends PC, I have connected it up to a spare monitor, It goes through the windows boot screens but when windows is supposed to be displayed, the monitor goes to standby.
I tried it on mt TFT monitor did the same thing, but instead of going to standby I got a message "OUT OF RANGE 800X600 H-53.7 V-85.1"

Any ideas what the problem could be??
Tried through a KVM switch, My pc is displayed ok but the other one comes up with the same error.

Just started the system I'm checking in Safe Mode and the display came up.
Tried changing the resolution on the system to 1025x768 but keeps dropping back to default.

its prolly a v old monitor, the "out of range" is for the frequency of the monitor in Hz

Try changing the refresh rate down to 60hz.