I just built a new system just a week ago and had the exact same problem. I thought "oh no...here we go..." But it turned out to be my monitory a CTX 17" from about 2001 or 2002 was too old. Even with the DVI to VGA adaptor the signal just could not be processed by the monitor. So I went to Costco and got the Viewsonic 19" LCD ...plugged it in and everything was perfect. Don't know if that is your problem but it did just happen to me.
And by the way...my monitor also just showed the orange lite