you must have fluorescent lights in your office?

They will flicker , some people are more sensitive to that that others.
The buzzing that some of those do drive me batty too.

Can you try some plug in lamps with something like the GE ? natural light bulbs? and turn off the overhead ones?
or the halogen ones that reflect the light off the ceiling?

Check the refresh rate on your monitor and set it as high as you can.
try different brightness/contrast combos on the monitor too.