Had a quick look on the net for others having this problem. A few things to try:
reseat the graphics card;
turn on the monitor first and give it a few minutes to warm up;
when you do get into windows, check the sync res is 60Hz or if it is, change it to 59Hz. check that the res is set to the native res for this monitor, which is 2560x1600 I believe;
check all connections,including power cord, between monitor and graphics card are fully pushed in;
check bios for any 'suspicious' settings relating to VGA/monitor which might need changed.