Monitor comes on with the power off

[RobTi]

Hi my mother called me to say that the monitor on her pc is flashing alternate colours while the plug For the pc is off at the wall , now the monitor is on an extension with the router and printer so powered on all the time. So usually she switches the pc on at the wall and it all just works but now even trying the switch on the monitor it goes off for around a couple of seconds with the amber power led then it wakes up to a green led and the screen flashing, so anything to check without visiting her ?
Thanks

 

[Regality]

My monitor used to do that when there was no input. Is it a Dell monitor? Is the problem that the monitor is no longer displaying the computers output or that it just flashes when the PC is off?

 

[RobTi]

Yes it’s a dell sorry don’t know if it works okay when the pc is on, as I got her grandson to just pull the plug on the mo it or. Saves me travelling to hers atm