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Is your Windows computer not booting up? It could be because of a hardware, software, or firmware error. This week, Kannon Yamada explains how to diagnose these problems, and how to fix them.
A Reader Asks:
So far, I’ve logged in the BIOS and changed to the default booting option, which didn’t help. I then disabled USB booting, changed UEFI to legacy support. Nothing worked. In some steps between, I got the message saying “checking media”, with two options, IPv4 and IPv6. Neither can be connected. Now I am desperate.
Maybe I have formatted the hard drive, or messed up the partitions. My laptop is Lenovo Y50, with 1TB of storage with 8GB of RAM, with no CD/DVD drive. Please help!
Got Windows boot problems? A Windows computer can fail to boot for one of three reasons: Bad software, bad hardware, or bad firmware. If you’re really unlucky, it can be a combination of the three.
In your case, the problem almost certainly relates to indiscriminate use of a data backup and recovery solution, which damaged your operating system’s software. For the purposes of comprehensiveness, we’ll also briefly cover the majority of troubleshooting methods for an unbootable Windows computer.
To my knowledge, there’s four kinds of common unbootable scenarios relating to Windows systems: There’s the Blue Screen of Death (BSOD); there’s a large number of unbootable machines with black screens; there’s a continuously rebooting machine, or bootloop.
A few other unbootable conditions exist, but these generally indicate a hardware failure, which often requires a more sophisticated troubleshooting strategy.
For Mac users, you can take a look at this step-by-step guide on what to do if your Mac won’t boot.
How the Windows System Boots
When you power any PC on, the Basic Input Output System (what’s a BIOS?) or Unified Extensible Firmware Interface (what’s a UEFI?) determines which partition to load, based on data it reads from the boot loader. In older Windows systems, we refer to the boot loader as the Master Boot Record (MBR). In Windows 10 the new boot loader is referred to as a GUID Partition Table (or GPT), although users can still employ the older MBR.
Depending on your system’s age, you might have either a BIOS or UEFI, which facilitates the loading of your boot loader. Newer systems rely on an UEFI, whereas older systems use the BIOS.
If either the MBR, GPT or core operating system drivers become damaged, you will experience an unbootable system. The difference between the two lies in the initial symptoms experienced by your computer while it boots. If you get a blue screen, that probably means the MBR or GPT successfully loaded and it failed to complete boot-up. If you get some other condition, like a blinking cursor amid the blackness of a DOS prompt, then the MBR/GPT might be damaged.
For the majority of boot problems, the Windows System Repair Disk provides the easiest solution.
Creating a Windows System Repair Disk
Making the repair disk just requires another Windows (7, 8, or 10) machine and a USB drive with at least 128MB of storage. Once you have the two, insert the USB drive and search for Create a recovery drive.
After selecting the program, and clicking through a confirmation window, choose the flash drive as your target for the recovery drive and select next.
Click through the next few windows. Your flash drive will be formatted, so make sure there’s nothing you can’t lose stored on it.
After the format finishes, you can then boot from the USB drive as if it were a DVD. You will use this disk to repair or diagnose your operating system. Here’s how to boot from a USB drive.
You will then need to restart your computer and boot from the Windows System Recovery Disk. Successfully booting from this disk varies from PC to PC. Most of the time, pressing a F10, F11, or F12 on boot will give you the option of booting into the drive’s recovery system. If you don’t know, try an Internet search for “USB boot” + your model of computer. For example, if you have a Dell XPS 13, search for the following:
“Dell XPS 13 USB boot”
How to Fix a Windows Blue Screen of Death
BSODs can occur because of either hardware or software problems. Although by far the most common cause originates in your operating system’s drivers. If there’s a damaged or missing driver which plays a key role in your system’s ability to boot, the entire system will fail to load.
So here’s what it looks like happened: You attempted to back up a partition on an Android smartphone and accidentally damaged Windows. Judging from the documentation for DiskGenius (which is now known as Partition Guru), it doesn’t seem likely that you erased any data storing partitions. If anything, it sounds like you’ve got some driver or hardware problems. We don’t know for certain though, so you’re going to have to do some sleuthing and troubleshooting.
Start off by plugging the error code or message from the Blue Screen of Death (BSOD) into a search engine. The BSOD should look something like this (except with a different error code):
So, to reiterate: Write down the error code.
Then shut the computer off and unplug everything that isn’t a power source or integral to the computer booting (like USB hard drives or external speakers). Then restart the computer. If the problem persists, then it’s not related to anything you had plugged into the computer. Next, boot into your Windows System Recovery Disk.
Once booted into the System Recovery Disk, choose the options Repair your computer and then Troubleshoot.
Then select Advanced options. In Windows 8, and 10 you have access to Automatic repair. The Recovery Disk should automatically repair any MBR or GPT faults. In Windows 7, you can choose to restore from a backup using System Restore or you can choose Startup repair (which is similar to automatic repair).
If this fails, you can also choose to refresh or reset your system (how to refresh Windows 8). If refreshing/resetting doesn’t work, check out how to fix Windows 8 if refresh fails. Keep in mind that choosing a refresh or reset will cause some data loss.
Our guide on fixing BSOD in Windows 8.1 covers most of the bases, but searching is always a good first step. If Google doesn’t provide any answers, I suggest attempting to reset or refresh your system using a Windows System Recovery Disk or a Windows (7, 8, 10) installation disk. We’ve covered in detail the steps required in making a Windows repair drive. Please read those instructions.
Fix Rebooting Windows
If Windows continuously reboots, in Windows 8 and above the operating system should automatically enter the System Recovery Options menu after the third forced reboot. Windows 7 and below will not do this automatically, which requires that the user manually tap F8 while booting. After tapping F8, Windows 7 (and Vista) will enter into the Advanced Startup Options menu.
Once inside the Advanced Startup Options menu, users can choose enter Safe Mode, restore to an earlier functioning state, and a more. Alternatively, they can enter the System Recovery Options menu, which works a bit like Windows 8 and 10’s recovery menu.
Here’s an excellent video on repairing a rebooting Windows installation:
Fix the Windows Black Screen of Death
There’s also the Black Screen of Death, which is far more difficult to resolve. Not only are there many different kinds of Black Screens of Death, there’s a variety of means to combat the problem. There’s two primary kinds of Black Screens: The blinking underscore and the black screen with a mouse cursor.
How to Fix Windows 10 Black Screen, Cursor
Windows 10 brings with it a new category of black screen Windows boot failures. Although technically, the machine did boot properly. The problem originates in the graphical drivers that Windows loads by default after installation. Windows 10 believes that it loaded the correct drivers, so the machine won’t automatically enter recovery mode.
Fix Windows Black Screen, Blinking Underscore
On boot, if your system displays a black screen with a blinking cursor, your hard drive isn’t detected properly. A common resolution entails heading into your BIOS or UEFI settings and toggling your drives connection standard from RAID or IDE mode to AHCI (or vice-versa). If that fails, you’ll want to change the boot order of your drives so that the drive containing the operating system shows up first in the boot order.
On Windows 7 (and older systems) sometimes changing your drive from IDE to AHCI will break your system. This requires installing a Microsoft Fix It executable, which adds AHCI compatibility to Windows 7.
Fix Windows Infinite Loading Screen
Windows can also enter an unbootable state where the Windows loading icon displays, but the system never boots. Sometimes this is caused by a flaky Windows update. Other times, it can show up out of the blue.
Unbootable Windows Hardware Problems
If your computer fails to pass Power On Self Test (what is POST?), that definitely means a hardware failure has occurred. James Bruce covered how to deal with hardware issues. His method revolves around attempting to narrow the cause of failure down to an individual, defective component, which means unplugging all non-essential devices and attempting to boot the machine. It’s the most basic troubleshooting methodology and no hardware repair guide is complete without it. However, a motherboard’s complexity requires a special troubleshooting process.
I’ve covered troubleshooting motherboard problems and how they can cause unbootable system states. Essentially, when the motherboard’s firmware isn’t working properly, users can resolve the issue using a few simple troubleshooting methods. The most effective of these is the deep reset, which temporarily halts power to the volatile memory on board all computers, thus resetting it to a factory fresh state.
Unfortunately, many Ultrabooks (what’s an Ultrabook?) and laptops don’t allow easy access to the BIOS backup battery. In this case, you would need to contact a skilled technician for additional support.
So Where Does that Leave Us?
You might notice that most of the repair methods revolve around using the Windows Recovery Disk. There’s a reason for this: The Windows Recovery Disk can resolve most boot problems. But for the most part, you will need to familiarize yourself with the Repair Tool in order to maximize chances of booting your system again.