So I just opened my Ubuntu in VM virtual box after a while in my Windows 10 PC.
It booted normally but when I place the cursor over the screen(in ubuntu OS) the screen starts to glitch.
I don’t know why it is happening since its the first time it ever has happened.

One more thing, when it first loads HOMEPAGE, the cursor is a gray box instead of the mouse pointer.

I tried to restart the VM Virtual Box but no change, the screen still flickers