Can some1 explain to me how refresh rate works, Ive read many articles saying higher refresh rate the better and less flickering, but when I set my refresh rate greater than 60 MHz my monitor flickers so much tat I think its worse for my eyes.

Higher refresh rate is better, but your monitor also has to support higher rates. Best practice is to set it at its default.(which is usually the highest rate it can safely operate at) Go to high for too long and you could do some serious damage to your monitor!

Not default! Default is the adapter's default and not the monitor's default, optimal (so long as the monitor is plug and play) will select the highest refresh the monitor says it can handle safely. I have a Mitsubishi Diamond Pro 730 which supports up to 160Hz, but this is never shown when I set to only display modes the monitor can cope with. As a rule of thumb you should set the refresh to AT LEAST 72Hz, this is sort of flicker free on most monitors (especially if you've used 60Hz). 75Hz is ideal and will not slow down graphics much at all. (The higher the refresh, the more work the graphics controller has to do to display the correct image on every refresh.) 85Hz is good if you think it's worth it, this will display a rock-steady image and higher isn't worth it as you will lose sharpness on the display. The max refresh of a monitor is just a guide to show what refresh is available at higher resolutions. Mine's at 1280x1024@85Hz Mike

Get yourself a decent monitor!

set the monitor to optimal settings there is an option there in display somewhere,