If you do not have an internal or external DVD drive or an external USB Hard Drive or Flash Drive and you want to get rid of your current Windows installation and replace it with Windows 8, then you can do it by following the procedure below.
What we need to do is boot from the Windows 8 Setup DVD but we don't have any external boot drives, so we need to place the Setup files onto a separate partition of the hard drive and then boot from the new partition as follows:
1. Create a small 4GB primary partition on the internal Hard Drive
2. Copy the Windows 8 Install Setup DVD files to the new partition
3. Install grub4dos
4. Reboot the system and boot to the 4GB Windows 8 Setup partition
5. Use Windows 8 Custom setup to delete the old Windows XP/Vista/7 partition(s) and install Windows 8 to the empty space.
For the sake of clarity in the instructions below, I will assume that you have Windows Vista already installed on one single partition (or perhaps two partitions). You could just as easily have Windows XP or Windows7 installed.
1. Boot to Windows and make a new empty 4GB primary NTFS partition at then end of the drive (using Vista Disk Manager can shrink/extend ptns).
If you have XP then download and install EaSeus Home Partition Manager.
It is best to have the 4GB partition at the end of the disk drive.
e.g. If you current partition arrangement is:
then first shrink the 490GB Windows partition as much as possible using Windows Disk Manager (Start Menu - Computer - Right-Click - Manage - Disk Management).
Next create a 486GB primary partition named DUMMY
Next create a 4GB primary partition and format it (Quick Format - NTFS). This can be called Win8Inst or any name you like.
we now have:
Thus the new 4GB partition is now at the very end of the drive.
2. Copy the contents of the whole Win8 Install/Setup DVD to the new 4GB partition. To do this you need either the (downloaded) ISO file or perhaps network access to another PC which has a DVD drive containing the Windows 8 Setup DVD. If you just have the ISO file you can mount the ISO file as a volume using SlySoft VirtualCloneDrive or Olof's ImDisk application, or extract the contents using 7Zip or WinImage, etc.
3. Install grub4dos onto the hard disk MBR (you can do this easily by downloading RMPrepUSB, hit Ctrl+F5 and then click on the Install grub4dos button - hit Enter and click OK when prompted to copy over the grldr file)
4. Copy the C:\grldr file to the new 4GB partition - IMPORTANT: Make sure the file grldr is on the root of the 4GB partition or it will not boot next time!
5. Reboot the computer - it will leave you at the grub4dos command prompt because you have no menu.lst menu file (if you get a menu because grub4dos has found a menu.lst file, then press C to get to the command prompt.)
6. Now type find to see what partitions you have - we need to boot from the 4GB partition - let us assume the new 4GB partition is listed as (hd0,3) (the 4th primary partition)
7. at the grub4dos prompt, type:
8. The hard disk should now boot to the Win 8 installer - enter the Windows 8 product key and choose Custom install - delete the other old Windows partitions (not the 4GB one!) and then select the empty space and tell it to install to the large free space.
After Windows 8 has been installed, the system will reboot back to Windows 8. The grub4dos bootloader will have been removed by the install. If you wish you can delete the 4GB partition now and use Windows 8 Disk Manager to extend the C: partition. Personally, I prefer to have 50% of the drive for Windows 8 and 50% for my data files, documents, mp3's etc. - thus I make two partitions when using the Windows 8 Installer Custom install dialogue. This way I can re-install Windows again at any time and not lose all my data files. I can also keep Windows backups on the 2nd partition. Therefore, you might want to consider making the 'Setup' partition larger than 4GB to begin with and keep that partition as a Rescue/Backup data partition.