Why does my screen flicker or show artifacts?
Screen problems divide into three layers, and identifying which one is at fault takes only a couple of tests.
The cable is the cheapest thing to rule out and a surprisingly common cause. Digital display cables either work or fail visibly, and a marginal cable produces exactly the symptoms people describe as flickering, sparkles or intermittent blackouts. Reseating both ends, and swapping the cable if possible, takes a minute and resolves a meaningful share of cases. High resolutions and refresh rates are far less tolerant of a poor cable than lower ones.
The driver is next. Graphics drivers are updated frequently, and both a stale driver and a freshly broken one cause visual corruption. If the problem began after an update, rolling back is a legitimate diagnostic step rather than a defeat. A clean reinstall of the driver, rather than an in-place upgrade, resolves cases where a previous installation left inconsistent files.
The hardware itself is the remaining possibility, and there are two useful tests to distinguish the display from the computer. Connecting a different display, or connecting this display to a different machine, isolates which side carries the fault. Watching whether the problem appears in the firmware setup screen before the operating system loads separates a hardware fault from a driver one, since no driver is loaded at that point.
One specific case is worth knowing. If flicker appears only at a particular refresh rate or resolution, the configuration is beyond what the cable or connection can carry reliably, and reducing one of the two will stabilise it immediately even though the display technically supports the setting.