@MariaG1000 Thanks for the screenshot. I have experienced something similar to this in the past, where boxes were appearing randomly on my screen after entering a formula in Excel. My particular problem was caused by compatibility issues with my NVIDIA graphics card. At the time, there was an option in Excel to "disable hardware graphics acceleration", but that option has since been removed. From what I've read, Microsoft has taken it upon themselves to maintain a list of compatible/incompatible graphics cards and drivers and apply the appropriate setting automatically. However, some people are still experiencing issues with this, as I would imagine some graphics cards have slipped through the cracks.
Personally, I haven't had any issues with random boxes appearing for quite some time now. The only thing I can attribute it to is the fact that I update my NVIDIA drivers regularly, whenever a new driver is available. It's possible that updating the driver for your particular graphics card may resolve the problem; however, I will leave that for you to decide.
As a preliminary troubleshooting step, you could temporarily disable "Hardware-accelerated GPU scheduling" in your PC settings. Go to Settings > System > Display > Graphics Settings then toggle off Hardware-accelerated GPU scheduling and reboot the computer. Note: I don't recommend this as a permanent fix, as it may affect the overall performance of other applications. However, it is a good first step to see if it's even related to the problem you're experiencing with Excel. After conducting some tests, you can always toggle this setting back on.
This is just a suggestion and is my "best guess" based on a similar problem I had in the past. If it doesn't apply to your situation, please disregard. :)
