IT FundamentalsA+

Display Troubleshooting for CompTIA A+ 220-1101

Display troubleshooting resolves monitor and display issues in desktops, laptops, and projectors. CompTIA A+ 220-1101 tests common display problems and their causes. Display issues are among the most visible hardware problems — users immediately notice a non-functional or degraded display, making rapid diagnosis critical.

6 min
1 sections · 7 exam key points
1 practice questions

Common Display Problems

No image / black screen: verify monitor power (LED on monitor, power cable). Verify video cable is connected at both ends. Try different video cable (cables fail — HDMI, DisplayPort cables can fail intermittently). Try a different video input (monitors have multiple inputs — ensure correct input selected on monitor). If laptop: external display works but internal screen is black — internal display cable or panel failure. If desktop: try integrated graphics port (remove GPU from PCIe slot first) — if that works, GPU is faulty.

Incorrect resolution or low resolution: appears blurry or elements look oversized. Cause: wrong display driver or driver not installed (Microsoft Basic Display Adapter shows at 1024×768 or similar). Fix: install correct GPU driver from manufacturer website (NVIDIA, AMD, Intel). OR: wrong resolution set — right-click desktop → Display settings → Resolution → select native resolution.

Flickering or flashing: loose cable connection (reseat cable at both GPU and monitor). Bad cable. Monitor refresh rate set too high for the connection type. GPU driver issue — update driver. Monitor hardware failure (slowly getting worse over time).

Discoloration or color issues: incorrect color temperature/gamma settings in display settings. Faulty cable (damaged pins in VGA cause missing colors). GPU hardware failure (partial VRAM failure can cause color artifacts). Single color tint — check cable connector for bent pins.

Dead/stuck pixels: dead pixel (permanently black — pixel receives no power), stuck pixel (permanently shows one color — pixel receives constant power). Test with a pixel-test image (solid red, green, blue, white, black screens). Warranty coverage: most manufacturers cover dead pixels above a certain threshold (e.g., 3+ dead pixels). Pixel-fixing software/videos cycle colors rapidly to attempt to unstick stuck pixels — effective for some stuck pixels, not for dead pixels.

Burn-in: ghost image of previously displayed static content permanently visible. OLED displays (smartphones, some monitors) are most susceptible. Prevention: screen savers, auto-dimming, avoid displaying static images long-term. Recovery: partial improvement possible by displaying rapidly changing content. Prevention is far more effective than recovery.

Key exam facts — A+

  • No image: check power, cable connections, correct input selected on monitor
  • Low resolution/blurry: install correct GPU driver — Basic Display Adapter = no driver
  • Flickering: reseat cable, check refresh rate, update driver
  • Dead pixel: permanently black; stuck pixel: permanently colored — different causes
  • VGA bent/damaged pin: causes missing color (one color channel lost)
  • Burn-in: OLED/plasma risk — prevent with screen saver, auto-dim; hard to reverse
  • Laptop no display: try external monitor to isolate internal display vs GPU failure

Common exam traps

A blurry or low-resolution display means the monitor is failing

A blurry or unexpectedly low-resolution display almost always indicates a software issue — the GPU driver is not installed (Windows loaded the generic Microsoft Basic Display Adapter) or the resolution setting is wrong. Installing the correct manufacturer GPU driver typically resolves this instantly. True monitor hardware failure is much less common and usually presents as flickering, dead pixels, or a complete image failure — not simply low resolution

Practice questions — Display Troubleshooting

These questions are representative of what you will see on A+ exams. The correct answer and explanation are shown immediately below each question.

Q1.After upgrading a GPU in a desktop PC, the monitor displays at 1024×768 and the desktop looks stretched. Device Manager shows 'Microsoft Basic Display Adapter.' What is the correct fix?

A.Replace the monitor with a higher-resolution model
B.Replace the GPU — it is defective
C.Download and install the GPU manufacturer's driver from their website
D.Increase the resolution in Display Settings manually

Explanation: Microsoft Basic Display Adapter is the generic Windows driver — it lacks knowledge of the GPU's capabilities and limits output to a low default resolution. The correct fix is to install the manufacturer's driver (NVIDIA, AMD, or Intel depending on the GPU). Once the proper driver is installed, Windows will detect the GPU capabilities and offer the full range of resolutions. Simply increasing resolution in Display Settings doesn't work without a proper driver — the option won't be available at the native resolution.

Frequently asked questions — Display Troubleshooting

How do you set up dual monitors in Windows?

Connect the second monitor to an available video port (HDMI, DisplayPort, USB-C with video). Windows typically detects it automatically. Right-click the desktop → Display settings. You'll see both monitors represented as numbered boxes — click 'Detect' if the second monitor isn't shown. Set the arrangement to match physical positions (drag the boxes). Under 'Multiple displays' select: Duplicate (same image on both), Extend (different content on each — most useful), or Show only on 1/2. Set each monitor's resolution and refresh rate separately. Primary display: the one where the taskbar and desktop icons appear.

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