I have a ATI radeon 5450 and the screen has got a bluish/purple hue to it when its connected via a VGA cable. However the HDMI output is normal. Its not the monitor or VGA cable as I have tried a different monitor and bought a new VGA cable.
Just use the DVI output then. Are you trying to hook up a second monitor? Because, if you are, you would be better off to use the digital outputs from the card, i.e. DVI, HDMI, and Display port. What is the manufacturer and Model of the card? What outputs are available on the back of the card? Also, assuming you're using a second monitor, do both monitors have a digital input such as DVI or HDMI?