Anyone who experience giddiness and eye pain should check their
windows Refresh Rate and always enable V Sync during gaming
especially if your monitor is CRT 
How to change refresh rate... u right click on ur desktop, go
properties, then from there go settings, click on advanced, the go
monitor. then from there u can see ur 'screen refresh rate', how
many hertz... basically it is how fast the screen refreshes itself.
if it is low, then it will certainly make a person feel giddy and
hurt the eye after some time, and when playing games, always enable
'v sync' if there is such an option.
If yours is a CRT monitor, chances are you can set your monitor
refresh rate to as high as 85, and if yours is LCD, probably
70.
and remember v sync, if possible, cos some games set the refresh
rate back to 60.
