Kindly note that assuming that you are utilizing a wrong media here - e.g. Windows 7 establishment Dvd on Windows 8 Pc, or 32-cycle form of Recovery Drive/system Repair Disc on 64-digit Windows - you can utilize the Command Prompt alternative just. While alternate choices are not crippled in the agenda, utilizing these closure with mistake messages and may harm your broken Windows establishment significantly more.
Step 1 - Automatic Repair in Windows 8 and 8.1
Unless you started Windows 8/8.1 Recovery Environment from a failed Automatic Repair attempt, the very first option to try in case Windows is unable to boot is the Automatic Repair that will check the condition of your hard disk and see if files needed to launch Windows are present. The process takes several minutes to half an hour.To access the option, click Advanced options in Troubleshoot screen.
In the Advanced Options screen, click Automatic Repair.
Next, choose a target operating system by clicking on its button. In most cases, you should have only one Windows 8 or 8.1 installation visible.
Windows will then look for problems on hard drive(s) and verify that all required files are in tact. This might easily take 10 or more minutes. Please stand by.
In case Automatic Repair was unable to fix problems, click Advanced options to access other recovery tools.
If repairs were successful, restart your computer.
Step 1.1 (optional) - use Command Prompt for fixing disk errors or restoring missing system files
If you do not have the correct Windows 8/8.1 installation or Recovery Drive/System Repair media, but you still need to check for and fix errors on disks, click Command Prompt in the Advanced Options screen.
A black Command Prompt window opens on drive with letter X. It is a special temporary disk created entirely in the Random Access Memory (RAM) of your PC. No hard disk space is used for this drive.
First, we need to locate the drive where Windows is installed. Most probably this is a drive with letter C, D, E or F.
Type echo list volume | diskpart and press Enter. This will display all drives available.
Ignore all volumes that have CD-ROM for Type.
The volume that has "System Rese" (part of "System Reserved") written in Label column, can also be ignored - this is the recovery partition. Such partitions are usually small in size - about 350 megabytes. Not all computers have the recovery partition.
So, in the example above, the Windows 8 partition has drive letter D (note the Ltr column). You can also use the Size column for verifying that you have located the correct one.
Now type chkdsk <the drive letter>: /F /X and press Enter. Replace <the drive letter> with the letter of drive where Windows is installed (or the drive that has files badly messed up), for example chkdsk d: /F /X or chkdsk c: /F /X.
This command will find and repair errors on the partition/volume (the /F switch) and if required, unmount it first (the /X switch).
If you want to run a full disk check with recovering data from unreadable clusters, use the chkdsk <the drive letter>: /R /X command instead. Note that the exhaustive test might take several hours to complete.
The process might take quite a while (up to an hour). After it is completed, verify that there is a line stating "Windows has checked the file system and found no problems" in the report. If there were errors on the volume, repeat the last command until the no problems message appears.
Ignore any failure messages about event log.
If there were errors detected and repaired, close Command Prompt by clicking the X mark on the top right. Click Continue in the Choose an option screen to try starting Windows normally and see if the problem has been solved.
If no disk errors were found, read on.
You can also try restoring missing system files using the SFC (System File Checker) tool. This is useful in cases where Windows boots up, but all you see is black screen with mouse pointer and keyboard shortcut Ctrl+Alt+Del does nothing.
Type sfc /scannow and press Enter. Let the scan finish, it will take about half an hour.
If you see the error message "There is a system repair pending which requires reboot to complete. Restart Windows and run sfc again.", use alternative command sfc /scannow /offbootdir=C:\ /offwindir=D:\Windows\ (replace D:\Windows\ with the correct drive letter or folder name if required).
Close Command Prompt window and and click Continue to see if this helped to get your Windows 8 PC running correctly again.
Step 1.2 (optional) - temporarily enable the F8 key for getting into Advanced Boot Options menu at computer startup
Because Windows 8 and 8.1 have no support for F8 key by default, you might be unable to get into Safe Mode or Low-resolution video mode for troubleshooting unless Windows starts properly. Somehow Microsoft couldn't foresee this vicious circle happening to many users.Luckily, you can enable the good old trick in the Command Prompt window described in Step 1.1 above. Please note that legacy boot options should not be turned on forever because they can cause trouble on UEFI systems. This is just a temporary workaround.
In the black Command Prompt window, type bcdedit /set {default} bootmenupolicy legacy and press Enter key. You should see "The operation completed successfully" message after this.
Close Command Prompt window and restart your computer. Pressing F8 key repeatedly before Windows starts loading should now bring up the older Advanced Boot Options menu.
To revert to the newer Modern UI version of troubleshooting tools, open elevated Command Prompt while Windows is running (use Window Key+X to open Quick Links menu and click Command Prompt (Admin)). You can also boot from Windows installation media or System Repair Disc/Recovery Drive and open Command Prompt in Recovery Environment.
Type bcdedit /set {default} bootmenupolicy standard and press Enter key.
Close the Command Prompt window and reboot your PC. Now your computer uses the Modern UI boot options again.
Step 2 - System Restore
The next step is to try System Restore from Advanced Options screen. This works only while using the correct Windows installation or System Repair Disc. Using Windows 7 media on Windows 8/8.1 installation (or vice versa) ends with an error message about no available Restore Points.System Restore will literally turn back time for your PC: while your documents and files will always remain in tact, all programs or drivers installed after the selected Restore Point might disappear and must be reinstalled. Also, if you changed your Local Account password recently, it might be reverted to the previous one by the selected Restore Point.
Please note that this System Restore cannot be undone (but you can still restore another Restore Point later).
