It sounds like your monitor may be experiencing a hardware issue, specifically with the LCD panel. Blue spots on the screen are often indicative of stuck or dead pixels, which can occur due to manufacturing defects or physical damage. Unfortunately, if it is a hardware problem, there may not be a simple fix.

First, I recommend checking your monitor's warranty to see if it's still covered. If so, contact ASUS support and explain the issue. They may be able to repair or replace the monitor for you.

If the warranty has expired, you can try a few things:

• Gently massage the area around the stuck pixels with a soft, clean cloth. Sometimes, this can help unstick them.
• Use a pixel repair tool software, which rapidly flashes colors to try and unstick the pixels. However, the effectiveness of these tools is limited.

Ultimately, if the problem persists and the monitor is out of warranty, you may need to consider replacing the screen or purchasing a new monitor.

I've had a similar issue with an ASUS monitor before. In my case, it turned out to be a problem with the monitor's backlighting. The blue spots were actually areas where the diffuser was damaged, allowing more blue light to shine through.

Unfortunately, this isn't something that can be fixed with settings or software. It's a hardware problem that typically requires either a repair or replacement of the monitor.

Here's what I'd suggest:

1. Check your warranty status. If it's still covered, contact ASUS support immediately.
2. If it's not under warranty, you could try opening up the monitor to check for loose connections, but this is risky if you're not experienced with electronics repair.
3. Get a quote for professional repair and compare it to the cost of a new monitor.

Good luck, and I hope you find a solution!