How do I troubleshoot problems that occur during boot?

Question

In the case that my computer would have issues with booting, what steps can I take to troubleshoot it?

Answer 1

Before we can start troubleshooting, you need to have an idea of how your computer boots.

How can I troubleshoot problems during the BIOS phase?

Essentially, you will want to work in a way which tries to exclude possible causes.

If your computer doesn't show a BIOS startup screen:

• Make sure your power is turned on, that your monitor is turned on and connected.
• Check if your Graphics Card is properly inserted, and that power is connected to the mainboard.

If your computer beeps or give you error codes very early:

• A list of quite some beep and error codes might help you determine the exact cause.

If none of the specific solution works or your computer hangs, crashes or does odd things:

• Try to reset the BIOS to bring the settings back to default.
• Disconnect any non-essential hardware that isn't required for the system to boot.
• Check the connections of all your power cables, external and internal ones.
• Check if your memory is properly inserted, try one memory slot instead of two if you can.
• Check if all the fans are working properly, if not, connect and clean them to avoid overheat.
• Check and see if any capacitors or transistors are damaged or blown-up.
• Try any hardware in another computer, if compatible, to see if it works there.

If your devices aren't detected properly:

Check the BIOS settings to see if is configured to detect the device,
your BIOS startup screen should indicate which key you need to press. (F1/F2/F10/F12/DEL)

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If the above troubleshooting steps don't help, there is probably something broken...

How can I determine which essential hardware piece is broken?

Your computer solely needs a power supply, mainboard, cpu, graphics card and memory lath to work.

The power supply, memory and graphics card can be replaced to determine if they cause the problem, if they don't then it's either the CPU or Mainboard. You can troubleshoot this with an useful flowchart.

Answer 2

How can I troubleshoot problems during the Windows Kernel phase?

Bad device drivers, bad services and corruption (due to hardware, software or virus problems) are the most likely candidates for problems during this phase. Your best bet is to try to get into the Safe Mode to see if you can troubleshoot more there or do a repair attempt with the Windows CD.

How can I remedy corruption to system files?

Windows has a System File Checker built-in, when it is ran it will attempt to check and restore any System files that have been corrupted. In case there was a disk problem or if a virus has tempered with one of the System Files, it might be able to cure the corruption.

Start a command prompt as administrator (WINDOWS + R cmd ENTER) and execute:

sfc /scannow

How do I configure my computer to start up with less so the problem doesn't load?

Using MSConfig, you can do a diagnostic start-up to see if that works and enable some things every boot to troubleshoot if one of those things was the issue.

How can I troubleshoot problems around the Windows Logon phase?

My computer executes things with make the Logon phase unfeasible.

From the Safe Mode you can use Autoruns for Windows to disable things you don't need; pay attention though, you might want to check twice what you disable because it also lists essential things. Try not to disable things by Microsoft, disabling the rest shouldn't harm but you might see otherwise...

Answer 3

Sometimes a simple chkdsk /r will restore the system to a bootable state when you get errors like "file missing" or "corrupt" messages before Windows loads.

chkdsk /r
scans and fixes files system errors and do a surface scan to locate/repair/replace any bad sectors.

chkdsk /f
scans for file system errors and repair them, no surface scan.

You can Boot from a XP CD or Vista/7 DVD and run it at the command prompt.

XP, run chkdsk /r from the Recovery Console

— Source

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In Vista/7, in the Recovery Environment command prompt run the command chkdsk C: /r

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chkdsk /r takes a while to run depending on the size of the disk.

The chkdsk log can be found in Event Viewer in XP, under Applications, as "Winlogon" events.

In Vista/7 it will be a recent event called chkdsk.

If the log shows any sectors being recovered, you should consider backing up your data immediately and replace the hard drive. On a othewwise healthy system, running chkdsk /f every month or so as maintenance is not a bad idea.