thanks DominicD for your help.I have win 7 isntalled.I opened that settings page u told.There my monitor's refresh rate is set to 60 hz also there is no option above this.Second option u told that is "Hide modes that this monitor cannot display" is not available to check.Pls see the image.
![](http://i55.tinypic.com/2qspksk.jpg)
You can also see above that monitor name is "Generic PnP Monitor" while my monitor's model is "Samsung B2030".Can you tell me whats wrong???
Also before LCD i had an CRT.That was fine.
Thanks again!