Problem connecting Apple Cin. Disp and Macbook

Hi all,

I am a new Mac user. I inherited a Macbook in October (it's now 1 year old) and have used it before with my 23" Apple Cinema Display. I have done this mostly by putting the laptop to sleep, closing the lid, connecting the 3 cables from the display to the laptop, and then tapping on the keyboard or mouse (both now using bluetooth) to activate the CD. I haven't connected the Macbook to the display in a while but now I get no response at all. As soon as I disconnect the monitor plug (but leave the USB and firewire), my laptop screen works fine, but no CD picture. Once I connect the monitor plug neither screen works.

A few other things. I have the power cord for the Macbook and the Apple CD plugged in. The small light at the bottom right corner of the CD is on so I am assuming I've got power to it and it's on.

I had tried different configurations with the display setting in system preferences based on online discussions I've found but none of these settings have helped. Just to be clear, I have been able to do this before so I know I have the right cables etc. Something in the settings must have changed or...

Any help appreciated.

Thanks.