My Dell 2407 WFPb won't stay in sleep mode when my laptop goes to sleep, even though the Dell did it until recently. "Entering sleep mode" flashes briefly, but than the Dell switches back to power-on mode, except the message "DVI-D cable not plugged in" now bounces around the screen. The DVI cable is plugged in at all times: it's a HDMI-DVI connector which worked fine as far as sleep mode until recently. I replaced all the caps on the Dell's power supply board just in case, but it didn't fix the problem (the monitor works OK otherwise, so I didn't break anything by replacing the caps). What else should I try? I don't want to discard the monitor just yet. I wonder if it may have something to do with Win drivers for the card (NVIDIA GeForce GT 230M, Win7 64). However, I don't think Win drivers can affect the card outside of Win, whereas the "DVI cable not plugged in" message flashes even at BIOS boot time, ie. before Win had a chance to load.