Troubleshooting Computers

Main topic

Power Issues

Check LED's

Check cables are
plugged in correctly

PSU Issues

POST Issues

Check Cabling

Faulty interfaces, CPU,
system firmware

Boot Issues

Check boot device

Is it powered on?

Check cabling

OS Issues

Blue Screen of Death

Scan QR code

Contact Support

Check format
of boot device

MBR

GPT

Beep codes

Use a multimeter

Try a good
known equipment

Driver Issues

Symptoms

Noises

Mechanical problems

Replacement

LED Activity

Device not
found

Corruption

Windows Disk
Management

Read/Write
failure

Bad sector

chkdsk

BSOD

Corruption

RAID failure

Driver failure

Replacement

Install latest backup

Component Issues

Symptoms

Shutdowns
Crashes

Software
Disk failure
Malware

Is there a pattern?

Thermal problem?

Check PSU
and other components

Run diagnostic tests

Perfomance Issues

Symptoms

Overheating

Check temperature
sensors

Clean cooling
system

Upgrade cooling
system

Misconfigurations

Incompatibility
issues

What has changed?

Run a
diagnostic test

Verify
compatability

Video Issues

Symptoms

No image on monitor

Cabling issues

Ensure cable is
attached correctly

Ensure cables is not
worn or cramped

Make sure cable is
compatable or powerful enough

Incorrect input channel

Ensure that correct channel
is set

Burned out bulb

Replace

Sudden shutdowns

Overheating

Clean cooliong system

Bad image quality

Dim image

Change the brightness and
contrast settings

Bad backlight?

Replace

Fuzzy image

Faulty video drive

Change resolution
settings

Flashing screen

Check cables

Bad display?

Flickering image

Replace

Dead pixels

Use software utilities

Gently press against display

Burn-in

Set sleep timer

Use a screen saver

Incorrect
color display

Color calibration

Check the cables

Audio issues

Ensure the external device
is working

Adjust output settings

What has changed?

Troubleshooting Networks

Cable/Adapter Issues

No connection

Use a cable tester

Use a loopback tool

Test on cable on
another computer

Update NIC driver

Network Speed Issues

Slow internet

Measure internet speed

Check for external
interference

Update NIC driver

Malware?

Scan for malware

Is every user experiencing
this issue?

Wireless Connection Issues

No SSID found

Out of range?

Configure connection
manually

Standard mismatch

Upgrade device

Check the radio
frequency

Weak signal

Move to a closer
location

Interference?

Adjust radio channel

Remove obstructing
objects

Use a WI-FI
analyzer

VoIP Issues

Latency

Jitter

Quality of Service
Mechanism

Limited Connectivity

DHCP issue?

Ensure DHCP functionality

Check patch cords

Check VLAN configuration

Access router management console

Troubleshooting Mobile Devices

Power and Battery Issues

Symptoms

No power

Check if the battery is properly seated

Check if the battery contacts are clean

Replace

Improper charging

Follow manufacterer's instructions

Monitor battery health

Swollen Batteries

Carefully discard the battery

Hardware Issues

Symptoms

Overheating

Use a cooling pad

Move device to
a cooler place

Remove dust from
cooling system

Use a monitoring app

Liquid Damage

Dry device

Clean circuit contacts

Replace battery

Screen Calibration Issues

Symptoms

Broken Screen

Replace

Digitzer Issues

Clean fingers

Ensure cabling is
connected correctly

Restart device

Replace

Cursor Drift

Decrease sensitivity

Restart

Replace

Connectivity Issues

Symptoms

Physical

Verify enablement

Ensure proper cabling
connectivity

Software

Move devices closer

WI-FI Analyzer

Malware Issues

Symptoms

Unresponsiveness

Overheating

High data usage

Unwanted feature utilization

Troubleshooting Printers

Connectivity Issues

Symptoms

Error Messages

Ensure that it is switched on

Esnure that cartriges are properly installed

Print a test page

Factory reset

Inspect Ethernet cable

Print Feed Issues

Symptoms

Paper jam

Use release levers to remove
paper carefully

Ensure good quality paper is
being used

Inspect roller

Replace?

Faulty static eliminator?

Paper feed issues

Verify correct paper size

Change rollers

Grinding noises

Check that all components are in place

Replace cartridge and maintenence kit

Print Quality Issues

Symptoms

Bad print image

The following defects are common in laser printers:Faded or faint prints—If a simple cause such as the user choosing an option for low density (draft output) can be discounted, this is most likely to indicate that the toner cartridge needs replacing.Blank pages—This is usually an application or driver problem, but it could indicate that a toner cartridge has been installed without removing its packing seals. Alternatively, if these simple causes can be discounted, this could also be a sign that the transfer roller is damaged (the image transfer stage fails).White stripes—This indicates either that the toner is poorly distributed (give the cartridge a gentle shake) or that the transfer roller is dirty or damaged.Black stripes or whole page black—This indicates that the primary charge roller is dirty or damaged or that the high voltage power supply to the developer unit is malfunctioning. Try printing with a known good toner cartridge.Speckling on output—Loose toner may be getting onto the paper. Clean the inside of the printer using an approved toner vacuum.Vertical or horizontal lines—Marks that appear in the same place (referred to as repetitive defects) are often due to dirty feed rollers (note that there are rollers in the toner cartridge and fuser unit too) or a damaged or dirty photosensitive drum.Toner not fused to paper—Output that smudges easily indicates that the fuser needs replacing.Double/echo images—This is a sign that the photosensitive drum has not been cleaned properly. The drum is smaller than the size of a sheet of paper, so if the latent image is not completely cleared, it will repeat as a light "ghost" or dark "shadow" image farther down the page. Images may also appear from previous prints. Try printing a series of different images, and see if the problem resolves itself. If not, replace the drum/toner cartridge.Incorrect chroma display—If prints come out in the wrong color (for example, if the whole print has a magenta tint), ensure that the toner cartridges have been installed in the correct location (for instance, that a magenta cartridge hasn't been installed in the cyan slot). Also ensure that there is sufficient toner in each cartridge. If there is a cast or shadow-like effect, the transfer belt or one or all of the cartridges or rollers are probably misaligned. Try reseating them, and then run the printer calibration utility and print a test page to verify the problem is solved.Color missing—If a color is completely missing, try replacing the cartridge. If this does not solve the issue, clean the contacts between the printer and cartridge.

Inkjet defects

Dirty print head?
Blocked ink nossle?

Dot matrix defects?

Print Job Issues

Symptoms

Backed-up queue

Restart print spooler

Garbled print

Update print driver

Configure PDL

Troubleshooting Windows

Boot Issues

Symptoms

Failure to boot/
invalid boot disk

Check for removable devices

Check drive connection

No OS found

Run chkdsk

Reset to default settings

Use the startup repair tool

bootrec

/fixmbr

/fixboot

/rebuildcd

diskpart

Black screen

WINDOWS+CTRL+SHIFT+B

chkdsk

sfc

Profile Issues

Symptoms

Slow boot

Enable Display highly detailed status messages

Corrupt profile

Rebuild profile

Create new account

Copy all data

Rebuilding a local user profile means creating a new account and then copying files from the old, corrupt profile to the new one, but excluding the following files: NTUSER.DAT, NTUSER.DAT.LOG, and NTUSER.INI.

Performance Issues

Symptoms

Sluggish performance

Monitor Task Manager

Close unnecessary processes

Restart

Check with software vendor

Update the system

Disable startup apps

Defragment the hard drive

Scan for malware

Low memory

Try to run less programs at
the same time

Upgrade

Low storage

Free up space

Upgrade

System Fault Issues

Symptoms

Blue Screen of Death

Faulty hardware

Enable Safe Boot

Use System Restore

Remove recently installed programs

Check components seatings

Run hardware diagnostics

Disable auto restart

Faulty drivers

Scan for malware

Write down error code and
investigate

Run chkdsk

System instability
or frequent shutdowns

Use Windows Memory Diagnostics

Run sfc

USB not working

Update driver

Use Device Manager and
remove and reinstall

Disable port

Use another port

Reduce the amount of devices
plugged in

Application and Service Issues

Symptoms

Applications crashing

Preserve data

Wait for response

Force stop

Check event logs

Update app

Uninstall and reinstall

Services not starting

Error message

Check Event Viewer

Restart the service

Ensure it is enabled

Ensure it has sufficient privilege

Scan for malware

Check system files

Use regsvr32

Use System Configuration Utility

Use Registry Editor

Troubleshooting Windows Networking

IP Issues

Symptoms

Limited connectivity

No DHCP server

Verify DCHP availability

No internet access

Router problem

ipconfig

Network reset

Local Network Connectivity Issues

Symptoms

Cannot connect to local devices

ping command

Devices not found

Remote Network Connectivity Issues

Symptoms

No internet connection

tracert command

Missing hosts

pathping command

Name Resolution Issues

Symptoms

No connection to servers
by name

Test if the problem relies on
one client only

If not, then problem is
on the server

If so, then only this client
has the problem

nslookup command

Network Ports Issues

Symptoms

No connection

netstat command

Troubleshooting Security Issues

Desktop

Symptoms

Performance Issues

Fails to boot

Slow

No internet access

Malware scan

Quarantine

Application Crashes

Security and services applications
not working

Quarantine

OS Updates fail

File System Errors

Changes to file permissions

Missing files

Renamed files

Notification alerts

Rogue antivirus

Antivirus scan

Browser

Symptoms

Redirection

Check HOSTS file

Check which DNS are able
to connect

Ceritificate warnings

Analyze certificate

Troubleshooting Mobile OS / Software

Mobile Device Issues

Process

Reboot

Android

Hold Power Button

Hold Power Button
(10 sec)

IOS

Hold Side/Top Button

Volume Up

Volume Down

Hold Side/Top Button

Factory Reset

Android

Settings

System

Advanced

IOS

Settings

General

OS Issues

Symptoms

Random reboots

Overheating

Faulty battery

Hardware diagnostics app

Replace and repair

Update OS

Faulty app

Uninstall

Slow performance

Overheating

Low battery

Too many open apps

Reboot

Free space

Uninstall

No orientation rotation

Ensure feature is enabled

Close apps that might be using it

App Issues

Symptoms

App fails to load / crash

Force stop

Clear cache

Disable

Uninstall

Reinstall

MDM

Connectivity Issues

Symptoms

Low signal

Low battery

Move devices closer

Remove physical barriers

Misconfiguration

Verify WI-FI standard

OS Update

AirDrop not working

Ensure sender is in recipient's
contact list

Security Issues

Symptoms

High numbers of ads

Fake warnings

Slow performance

No internet connection

Unexpected app behavior

High network traffic

Monitor data usage

Leaked data

Breach

2 step authentication alerts

Disable location
tags on photos