LCD Monitor Problem - Any LCD Experts Here?

My LCD monitor is about 3 years old.

The model is BenQ FP91G+.

I am currently using the onboard graphic card which is Radeon Express 1250 on M2V-VM all in one Asus Mobo.

The monitor seems to be blindingly bright, especially with white color. It seems as if the screen is flickering even though I don't think it is. The symptoms on my eyes seem similar to the condition after watching at a low refresh rate for awhile. The monitor is currently set on 75 Hz. My eyes get tired fast and literally hurt a bit if I use the websites with white background for awhile. When running a movie or a video, there doesn't seem to be much of any problem.

The problem started after formatting recently. I had to format because the computer would, for some reason, lock up when there is a signficant CPU load. When the computer froze, I had to reset the computer by manually turning off the power. I did this about 8+ times to sort and obtain the necessary files before formatting. I wonder if that hurt the monitor.

I didn't have this problem before formatting. Remember: I have been using this monitor for the past 3 years. Adjusting the gamma/brightness isn't the issue here. I tried different setups and they weren't the main issue that was causing the problem, meaning it isn't the solution. Again, I don't have any problem viewing videos.

I would like to know if this is a problem with the aging of the monitor or a problem with the onboard VGA.

Thanks in advance.