Question I have a Walmart computer "HP Slim Desktop S01-pF1xxx" with a strange screen phenomenon

[rickety_goodman]

Whenever the computer is on, there is a full-height, single-pixel-wide vertical bar that slowly slides back and forth across the screen from about 1/3 to 2/3 of the width of the screen. Absolutely nothing affects it, although one time I walked off and left it to find it missing when I returned. It soon reappeared.
A second curiosity: the windows icon on the lower left of the task bar which is normally blue: it's now normally black and turns blue when you mouse over it.
All of this is also there when I'm using powershell or CMD under powershell!

 

[Ralston18]

Update your post to include full system hardware specs and OS information.

PSU: make, model, wattage, age, condition (original to build, new, refurbished, used)?

Disk drive(s): make, model, capacity, how full?

= = = =

Try running the built-in Windows Troubleshooters. The trouble shooters may find and fix something.

Manually download the GPU drivers directly from the applicable GPU manufacturer's website. Reinstall and reconfigure.

Perhaps corrupted files.

Try "sfc /scannow" and "dism".

References:

https://www.lifewire.com/how-to-use-sfc-scannow-to-repair-windows-system-files-2626161

How to use DISM command tool to repair Windows 10 image | Windows Central