A clean Installation of Windows 8
You need to be more detailed on how to backup your personal data and to advise how to partition a drive if needed, especially in a single hard drive configuration like laptops.
a. Personal Data - have all you date included in My Documents; this should be a disciplined act during normal computer usage. Go to C: drive and open Users. Here select your folder i.e. John or Richard or LivingRm etc. in your folder are a list of folders including My Document. For each of the folders right-click > Properties > Location > change the location to a USB or external drive. All your files are copied and saved away from the C: Drive.
b. Partitioning Hard Drive during a Window 8 Installation - A typical laptop hard drive is always bought with a C: Drive partition and no D: Drive. Place a D: Drive after the process of deleting the partitions during Windows 8 installation. A good size would be between 80 and 120 GB. Do not attempt to format D: Drive during installation because it will place a boot sector. Format the second drive once your in and working with Windows 8 through the Disk Manager program.
c. Personal Files after Installtion - Copy your personal files to D: Drive first. Now go to C: Drive to the User Folder and select your personal folder John or Richard etc. If the folder is named differently from the previous installation, change the old folder to reflect the new name 1st. Then in C: Drive > Users > "John" right-click each of the folders select Properties then Location and change everything to D: Drive.
This method protects you from a corrupt OS where you may freely and tirelessly reinstall without effecting personal data. Having a second partition (D: Drive) allow you to use an imaging program and store the image; this cannot be done on a singe partitioned hard drive unless it is transferred to an external hard drive.