How to stop flickering on Dual Monitors

I am trying to configure a Dual Monitor system. I have two LCD here. The first one is Gateway FPD2185 LCD and the second one is SynMaster 730B. Now both of them is not working. When I start Vista, it stuck on the logon screen. The monitor looks to be working fine with bios screen and I can even see Vista boot logo. But when I log in to my account there is constant flickering and sometime it is totally black. I have Radeon 9800 Pro GPU installed in my system. I had updated and installed the most latest ATi Catalyst drivers. But still the issue is common.

Did you to check the connectivity stuff. Check your cables. Go to settings and see you can adjust the right resolution. Because this kind of things does not work if there is no updated drivers. Old drivers are common cause of this problem. You can try checking that you are using the right edition. Like driver specially for Vista. A fresh bios update also helps the motherboard to work with gpu in more proper way.