Problems with external monitor

[roguerower]

I have a Acer Monitor and have owned it for about a year and half with no real problems. However starting bout 6 months ago, the screen starts flickering, not on and off, just varying shades, sometimes not enough to notice. However when I play a game in windowed mode and it's a black background it is really noticable. Its set to the stantard 60hz refresh rate. I'm using an old (3 yrs) dell m70 w/ a quadro fx go1400 video card. I've tried screwing around w/ the monitor settings but hasn't changed...any ideas?

Edit: I have a set of logitech speakers sitting right next to it w/ the base underneath the desk. The laptop sits next to it on a cooling pad. Dunno if it's relavent but just wanted to throw it out there.