A Windows 7 clean install simply means an installation of Windows 7 on an unused partition on your hard drive. In most cases, though, a clean install of Windows 7 means to remove an existing operating system (Windows XP, Linux, Windows 7... doesn't matter) and to replace it with a fresh installation of Windows 7.
After serious Windows 7 problems or during a new Windows 7 installation with an older operating system installed that you'd like to replace, it's best to wipe your primary hard drive partition clean and install Windows 7 from scratch - a procedure referred to as a "clean install" or sometimes as a "custom install".
The most important thing to realize before performing a clean install of Windows 7 is that all of the information on the drive that your current operating system is installed on (probably your C: drive) will be destroyed during this process. That means that if there's anything you want to keep you should back it up to a CD or another drive prior to beginning this process.
You should also locate the Windows 7 product key, a 25-digit alphanumeric code unique to your copy of Windows 7. If you can't locate it, there is a fairly easy way to find the Windows 7 product key code from your existing Windows 7 installation, but this must be done before you reinstall Windows 7.
Step 2 - Boot From the Windows 7 DVD
To begin the Windows 7 clean install process, you'll need to boot from the Windows 7 DVD.
- Watch for a Press any key to boot from CD or DVD... message similar to the one shown in the screenshot above.
- Press a key to force the computer to boot from the Windows 7 DVD. If you do not press a key, your PC will attempt to boot to the next device in the boot order, which is probably your hard drive. If this happens, chances are your current operating system will boot.
Note: If you existing Windows installation begins to boot or you see a "No Operating System Found" or "NTLDR is Missing" error here instead of the screen above, the most probable reason is that your PC is not setup to boot to the CD/DVD drive first. To correct this problem, you'll need to change the boot order in BIOS to list the CD/DVD drive first.
You don't need to do anything at this point but wait for Windows 7 to finishing loading files in preparation for the setup process.
Note: No changes are being made to your computer at this time. Windows 7 is just temporarily "loading files" into memory for the setup process. You'll be removing everything on your computer as part of the Windows 7 clean install in a future step.
After the Windows 7 install files are loaded into memory, you'll see the Windows 7 splash screen, indicating that the setup process is about to begin.
Step 3 - Choose Language and Other Preferences
Choose the Language to install, Time and currency format, and Keyboard or input method that you'd like to use in your new Windows 7 installation. Click Next.
Step 4 - Click the Install Now Button
Click on the Install now button in the center of the screen, under the Windows 7 logo.
This will officially begin the Windows 7 clean install process.
Note: Do not click the Repair your computer link at the bottom of the window even if you're completing this clean install of Windows 7 as part of some larger repair project for your computer.
The Repair your computer link is used to start a Windows 7 Startup Repair or perform another recovery or repair task from System Recovery Options.
Important: If you're performing a clean install of Windows 7 as a solution to a major problem but have not yet tried a Startup Repair, do that first. It could save you the trouble of completing this clean install process.
The Windows 7 setup process is now beginning.
Step 5 - Accept the Windows 7 License Terms
The next screen that appears is a textbox containing the Windows 7 Software License.
Read through the agreement, check the I accept the license terms checkbox under the agreement text and then click Next to confirm that you agree with the terms.
Note: You should always read "small print" especially when it comes to operating systems and other software. Most programs, Windows 7 included, have legally binding limits on how many computers the application can be installed on, among other limitations.
Step 6 - Choose the Type of Windows 7 Installation to Complete
In the Which type of installation do you want? window that appears next, you're offered the choice of Upgrade and Custom (advanced). Click on the Custom (advanced) button.
Step 7 - Show the Windows 7 Advanced Drive Options
In this screen, you'll see each partition that Windows 7 recognizes.
The main difference in a Windows 7 clean install verses other kinds of Windows 7 installation methods is that a clean install involves the removal of all operating system related partitions.
Windows 7 setup considers partition management as an advanced task so you'll need to click the Drive options (advanced) link to make those options available.
In the next few steps you'll delete the partitions containing the operating system you're replacing with Windows 7, be it Windows Vista, Windows XP, a previous installation of Windows 7, etc.
Step 8 - Delete the Partition Windows is Installed On
Now that all available drive options are listed, you can delete any operating system related partitions from your existing hard drive(s). (all music, all video, all documents, etc.)
Step 9 - Confirm the Partition Deletion
After deleting the partition, Windows 7 setup will prompt you to confirm the deletion.
The message says "The partition might contain recovery files, system files, or important software from your computer manufacturer. If you delete this partition, any data stored on it will be lost." Click the OK button.
Step 10 - Delete Other Operating System Related Partitions
If there are any other partitions that need to be deleted, you can do so at this time.
For example, the Windows 7 installation I had on my PC previously created this special 100MB (very small) partition to store system data in. This is most definitely related to the operating system that I'm trying to completely remove from my computer so I'll delete this as well.
Highlight the partition and click the Delete link.
Step 11 - Confirm Additional Partition Deletions
Windows 7 setup will prompt you to confirm the deletion of this partition. Click the OK button to confirm.
Step 12 - Choose a Physical Location to Install Windows 7 On
As you can now see, all the space on the installed hard drive is unallocated. No partitions exist on this computer.
Note: The number of partitions displayed and whether those partitions are unallocated portions of a hard drive, previously partitioned spaces, or previously formatted and blank partitions will depend on your specific system and which partitions you deleted in the last several steps.
If you're installing Windows 7 on a computer with a single hard drive on which you've just deleted all the partitions from, your screen should look like the one above, aside from your hard drive being a different size.
Choose the appropriate unallocated space to install Windows 7 on and then click Next.
Note: You do not need to manually create a new partition nor are you required to manually format a new partition. Windows 7 Setup will do this automatically.
Wait While Windows 7 is Installed
Wait While Windows 7 is Installed
Windows 7 Setup will now install a clean copy of Windows 7 to the location you chose in the previous step. Just waiting for it.
This is the most time consuming of any of the 34 steps. Depending on the speed of your computer, this process could take anywhere from 5 to 30 minutes.
Step 13 - Restart Your Computer
Now that the Windows 7 clean install process is nearly complete, you need to restart your computer.
If you do nothing, your computer will reset automatically after 10 seconds or so. If you'd rather not wait, you can click the Restart now button at the bottom of the Windows needs to restart to continue screen.
Wait for Windows 7 Setup to Begin Again
The Windows 7 clean install is now continuing. There are a few more automatic Windows 7 setup steps to come.
Wait for Windows 7 Setup to Update Registry Settings
Windows 7 Setup is now updating registry settings in preparation for the final stages of the operating system clean install.
Wait for Windows 7 Setup to Start Services
Wait while Windows 7 Setup starts various necessary services. This starting of services will occur during every Windows 7 boot as well but you won't see it like this again. Services start in the background during a normal Windows 7 startup.
Wait for Windows 7 Setup to Complete
This last Windows 7 Setup screen says "Completing installation" and may take several minutes. All you need to do is wait - everything is automatic.
Wait for Your PC to Automatically Restart
Wait while the Windows 7 setup process automatically restarts your computer.
Important: Do not restart your computer manually at this point. Windows 7 Setup will restart your PC for you. If you interrupt the setup process by restarting manually, the clean install process may fail. You may then need to start the Windows 7 setup over again from the beginning.