Windows 7 allows creating a bootable System Repair Disc - CD or DVD that boots right into Repair your computer options. This disc launches the so-called Recovery Environment (RE), and it cannot be used to install Windows. You can also create the disc in Safe Mode of Windows 7.
The disc is meant for those who do not have a bootable Windows 7 DVD - this is a common case as there is no DVD bundled with computers that have Windows 7 preinstalled (the OEM versions of Windows). It is strongly recommended to create the disc before getting into trouble - if you cannot start Windows 7 in Safe Mode, you might be out of luck in repairing your PC.
Please bear in mind that a 32-bit (x86) Repair Disc can only be used to fix 32-bit Windows 7 editions and a 64-bit (x64) Repair Disc works with 64-bit Windows 7 editions only.
A good thing is that you can repair any edition (Starter, Home Basic, Home Premium, Ultimate, etc) of Windows 7 with this disc, as long as it is meant for the same hardware architecture (32-bit or 64-bit).
The same option was available in Windows Vista before Service Pack 1, but Microsoft decided to remove it for some reason. Windows XP has no equivalent to this disc; Windows 8/8.1 and 10 have Recovery Drive with enhanced repair features.
Please note that the System Repair Disc is not a backup of your files or your computer.
First, make sure you have a blank CD or DVD. And I really mean blank, because the program is not capable of overwriting rewritable media. You can blank a CD or DVD by opening Computer, right-clicking a CD/DVD writer in the list and selecting Erase this disc.
To create the disc, open Start menu and type "repair" into Search box. Click Create a System Repair Disc.
Create a system repair disc opens. Make sure you have inserted a blank media and click Create.
Error "The files needed to create a system repair disc were not found on this computer" means that winre.wim file is missing. The easiest way to resolve this is to insert Windows installation DVD. If you do not have one, see the Restore Windows RE tutorial.
The process start with preparing files for the media. This takes up to a few minutes.
After this, the files will be burned to the media. This might take up to 5 minutes.
If an error stating "The disc in the selected drive is not blank. You must erase the disc before you can use it." appears before creating the disc, the media is not blank. Click OK and erase the disc as described above. Then return to this program and click Create again.
After the process has completed, an overview of the disc capabilities appears. Please note the suggested label - this defines whether you can use the disc for repairing 32-bit or 64-bit editions of Windows 7.
Click OK and close the program.
Here's the list of files that a typical Windows 7 System Repair Disc contains.
To see the sources\boot.wim file in Windows Explorer, you might have to disable the Hide protected operating system files (Recommended) option temporarily. See the Change folder views and options in Windows article for instructions.