1. On the C: drive, create a new folder named Refresh. If prompted, click/tap on Continue.
2. Insert/Connect your Windows 8 installation DVD/USB, or mount your Windows 8 ISO file. Navigate to and open the sources folder. Search for the install.wim file.
3. Select, then copy the install.wim file.
4. Go back to the C:\Refresh folder.
5. Paste the install.wim file into the Refresh folder. If prompted, click/tap on Continue.
6. Open an elevated command prompt.
7. Copy and paste the command below, and press Enter.
reagentc /setosimage /path C:\Refresh /target C:\Windows /index 1
To Revert:
Credits goes to wins for the revert section.
1. Run notepad as an administrator.
2. Click/tap File, then Open. Navigate to:
C:\Windows\system32\Recovery
3. Change the File type to All Files, then select the ReAgent.xml file
NOTE: It is highly recommended for you to make a copy of this file before proceeding.
4. Scroll to the right until you find:
OsInstallLocation
5. Change it to this:
<OsInstallLocation path="" id="948075900" offset="0" guid="{00000000-0000-0000-0000-000000000000}" index="0"/>
NOTE: Leave the id and guid intact. Don't make changes to id and guid.
6. Save it.
That's it.
Now you can Refresh/Reset Windows 8 without install disk.