PC / Computer randomly reboots and then warns to run Chkdsk

Hard disk drive problem: PC reboots randomly and warns to run chkdsk hard-drive diagnostic tool

My desktop PC runs Windows 7 Professional. Sometimes it reboots of its own accord. Recently, at startup, dire warnings appeared asking me to run Chkdsk with a surface scan. It seems to be getting worse with time. I have tested the AC mains power cable with a continuity meter and removed and re-seated the memory modules, the hard-disk-drive power connector and connection to the motherboard. The hard disk drive is a Samsung M9T 2TB model, so I tested it with Samsung’s hard-drive diagnostic utility, which reported no problems. The surface scan performed by Chkdsk itself was successful. I have also removed and replaced the silicone heatsink compound between the processor and the cooling unit.


It is advisable to begin by removing all of the removable components connected to the motherboard (memory modules, graphics, sound, network cards, etc.) so that you can clean their contact points and then re-seat them. You should also inspect the motherboard’s capacitors, which are the large cylindrical objects wired to it, for any signs of bulging or leakage. The capacitors regulate the power supply to components such as the memory modules. If one or more of them are failing or failed, voltage drops can occur that make the computer reboot.

Using a boot CD/DVD as a diagnostic tool

Spontaneous reboots can also be caused by software, such as a corrupt or bad device driver. To make sure that this is not the case, try booting the system from a CD/DVD with its own bootable operating system. To boot the system from a CD/DVD means having the CD/DVD drive set as the first boot device in the BIOS or UEFI BIOS.

You could try using the free Ubuntu Linux from ubuntu.com. You can also buy cheap, ready-made bootable Linux DVDs if you are using a slow dial-up connection. The download of the ISO file that you download and then burn to a CD/DVD using the “Burn a disc image” option of CD/DVD burning software, is a huge 700MB+ download.

Many brand-name PCs, including most Dell PCs, come with built-in diagnostics that bypass Windows. A particular brand-name PC’s diagnostic software can also be provided on a CD. If so, try using it. I have tried using these diagnostics on a few occasions and the Windows Troubleshooters for this kind of problem, but not with much success, unfortunately.

The Ultimate Boot CD

The Ultimate Boot CD from http://www.ultimatebootcd.com/ contains several diagnostic programs and is self-booting. It is worth using. The download is free; you pay a small fee for the CD itself. Note that it is fairly difficult to create the CD. Read the FAQ page here: http://www.ultimatebootcd.com/faq.html

It could be difficult to determine the cause of the rebooting if the computer only reboots once a day. You might have to leave it running all day or longer to find out if the reboots were caused by hardware.

You can use the MHDD utility on the Ultimate Boot CD to check the hard disk drive for intermittent lockups that Chkdsk or the drive manufacturer’s diagnostic utility didn’t detect. You can also download MHDD – a free hard-drive diagnostic utility – from http://hddguru.com/.

In any case, if you have the Ultimate Boot CD, run its memory tester. Just remember to set the CD/DVD drive to the first boot device in the BIOS or UEFI BIOS so that the system boots from the CD that you created.

Updating the device drivers

If your computer reboots while running any of these options from a boot disc, you then know that the problem is hardware-related, not software-related. If the computer runs utilities without rebooting, then the problem is being caused in Windows by software, such as a bad device driver. If the cause is a bad driver, it could be fixed by downloading an installing the latest drivers for all of computer’s devices from their manufacturer’s sites.

Some computers provide live device-driver updates. For example, laptop or desktop computers that are made by MSI, or which have an MSI motherboard, have the MSI Live Update feature that scans the system for updates and allows you to choose which drivers to install. You run the utility while online. It shows the version that is installed and the online version. If the online version has a higher number, an update is available that you should install. As a last resort you can also make use of Windows Update, which provides also third-party drivers as non-essential updates that you can choose to install. Note that Windows Update is known to install the wrong drivers.

It is always advisable to create a restore point in System Restore before updating the system in case you have to roll the system back in normal mode or in Safe Mode. The free Belarc Advisor can be used to identify the hardware (and software) installed on a computer, which can be used to find out which device drivers to update. Sites that provide driver updates should be avoided, because, in my experience, most of them are no good.

Actions to take if it’s a hardware problem

If one or more reboots occurs while the alternative operating system is running, you have to look for a hardware cause. If the power cable that connects the computer to the mains supply is old, replacing it may fix the problem. The connector that fits into the back of the computer can often be loose-fitting and not make good contact. Moreover, the fuse holder that holder a fuse in the 13A plugs used in the UK can be the source of another improper connection.

Since Windows 7 was insisting on performing a surface scan on the hard disk drive, it could not read or write to a particular area or areas of the drive. During the scan, it marks any unusable clusters as bad so that the system won’t use them. It also attempts to move data from them. The Event Viewer logs should provide useful details. You can bring it up by pressing the Windows key (the one with a flag on it) plus the R key and entering eventvwr.msc in the Run box that comes up.

However, note that it is possible but rare for a hard-drive problem to cause a computer to reboot; such a problem is far more likely to cause a computer to lock up. It is far more likely that faulty memory, motherboard or processor has created a corrupt command that has been sent to the hard disk drive, thereby creating an apparent but not actual disk error that is causing the computer to reboot.

If the problem is being caused by a faulty power supply, motherboard, processor, or memory, the only way for a home user to find out which component is responsible is to take the computer’s base unit to a reputable computer repair shop, or swap those components with known good ones until the culprit is discovered.

About Eric 275 Articles
I am an experienced PC technician who has been the owner and sole writer of the PC Buyer Beware! website since 2004. I am learning all the time in this very dynamic, ever-changing field.