monitor constantly stands by and wakes up

This is driving me nuts, I cannot put my monitor in standby. As soon as it does so, it immediately switches back on. No idea whats going on, and no freeware to tell your monitor to standby. I can't d/c the cable because dvi doesn't always act "plug n play" like doing this with a vga monitor. And I am told it's bad to turn on and off an lcd every day, its better to leave it in standby.

Can someone please help?

Bad to turn an LCD off? certainly not.