One problem I have had with a computer has been where the computer got part way through booting Windows and then rebooted itself. This happened over and over with the only difference on the subsequent occasions being that because Windows hadn't shut down properly from the first boot attempt it brought up the menu offering to start in safe mode on the subsequent boots. Whatever mode was selected made no difference though and every time it would get part way through booting windows then crash and reboot.
The first thing that occurred to me was that this was being caused by a hardware problem in the computer. To eliminate as many hardware issues as possible I unplugged those components not absolutely necessary to boot the computer. I also disconnected and reconnected everything else just in case it was a loose connectio causing the problem. None of this made any difference.
That Windows was actually starting to boot indicated that the computer was actually at least starting to read from the hard drive. The next thing that I decided to try was to place the Windows CD in the DVD drive and see if the computer would boot from that.
The computer would indeed boot from te CD indicating that the problem was almost certainly with either the hard drive itself or that the copy of Windows on the drive was damaged. I decided to try going into repair mode by typing R at the appropriate spot in the boot process (going past that point without typing R would have started reinstalling Windows and I didn't want to do that).
The repair console opened giving me a command prompt The most obvious thing to try at this point was to try a dir command to display the directory of the hard drive. The command failed producing an error message indicating that the file structure on the hard drive was corrupted. Well that at least explained why Windows was refusing to boot but what to do to fix it? Reformatting the drive would fix any software corruption but would mean that we'd lose all the data on the drive that wasn't backed up and would need to spend days reinstalling all the software. Also there'd still be no guarantees that it wasn't a hardware problem with the disk and that after spending all that time that I'd be back where I started.
The next thing that occurred to me was to run a chkdsk to see what it reported (chkdsk with no parameters is the command line equivalent of thw windows scandisk option, when you select options with scandisk the computer actually schedules a chkdsk with the appropriate parameters for the next boot). With no parameters the command reported that the drive was not flagged as dirty and so the command would not be run. Adding the -p parameter forced the chkdsk to run and then it reported that there were errors found on the drive.
I then ran the chkdsk -r command to attempt to repair the errors on the drive. It took quite some time to run a scan and repair and a couple of times the scan had to backtrack with the percentage complete falling rather than clinbing as it rescanned the repaired sections but the command finally completed successfully advising that it had repaired several errors.
Rebooting from the hard drive was now successful and I logged into the admin account to check things out further. Windows reported that the registry was corrupted and that it had needed to use a backup copy in order to boot successfully. I then tried rebooting the computer several times and each time the computer rebooted successfully.The problem appeared to be resolved.
The following day the same problem came back with Windows yet again refusing to boot. I repeated the repair process which allowedme to get into Windows. Obviously further action would be required to fix the problem permanently.
The obvious solution is to replace the hard drive with a new one and to do a drive image from the old drive to the new one so that any hardware corruption on the drive can be eliminated as the cause. That requires both a replacement drive and drive imageing software neither of which I had available at the time. So in the meantime I decided to try a few other software options.
There were two things I could think of to do next. One was to make a copy of as many of the files from the drive to a backup drive as possible so as to minimise the loss of data if the drive completely failed. Of course I already had multiple backup copies of all the actual data files but now I was trying to back up as many of the windows and application program files as well. That would hopefully speed up the process of getting everything running again of the drive did fail before I could take an image of it to a new drive. The other thing it occurred to me to try was to run a defrag of the drive. This rearranged the files on the drive placing the pieces of each file next to one another rather than their being scattered all over the disk. While certain files need to be in specific spots on the disk I was hoping that if the problem was caused by a critical file that was moveable being on a bad spot on the disk that the defrag would hopefully move that file to a location on the disk that wasn't damaged.
Replacing the hard drive was of course the next step so as to ensure that the problem wouldn't occur again. I made sure that was done reasonably quickly to ensure that the hard drive didn't fail totally before I could copy everything across.
This article written by Stephen Chapman, Felgall Pty Ltd.