Check your resolution.
Question: Has it been always blurry? If so, it may be the LCDs are slow in response to the video input. In this case, get a new high resolution fast LCD monitor.
Changing the screen resolution doesn't help, still blurry.
It's been a great monitor with no blurriness until the last couple of weeks. How do I check the graphics drivers?
If so, your problem isn't your monitor ~ it's you.
See your optometrist and he'll probably give you a referral to an opthamologists.
It's possible you have macular degeneration too.
Prepare for the worst. Accept the best.
Click on Display Adapters then the drivers tab. Note dates and version then go to the manufacturer's website to see if their date on the newest driver for that model is more recent than yours. If the dates are more recent then download the new driver. Also do this with your monitor if the dates are the same then there's nothing more to do.