It looks like you will be able to do a clean install just found this on MS..
Installing and reinstalling Windows
In this article you will find instructions for:
Upgrading to Windows 7. Choose Upgrade to keep your files, settings, and programs from your current version of Windows, and if your current version of Windows can be upgraded. If your version of Windows can't be upgraded, you need to choose Custom.
Installing a custom version of Windows. Choose Custom to completely replace your current operating system, or to install Windows on a specific drive or partition that you select. You can also use Custom if your computer doesn't have an operating system, or if you want to set up a multiboot system on your computer. For more information about setting up a multiboot system, see Install more than one operating system (multiboot).
Reinstalling Windows 7. Choose this option if you want to restore default Windows settings or if you are having trouble with Windows and need to reinstall it by performing a custom installation.
During the installation process, you need:
The Windows installation disc or the Windows installation file if you purchased and downloaded Windows 7 online. Purchasing and downloading Windows 7 online is an easy way to install Windows 7 on a netbook or other PC that doesn't have a DVD drive. For more information, go online to the Microsoft Store.
If you are a student, you might be eligible to buy Windows 7 at a discount. For more information, go to the 741 webpage, and then click BUY.
An external DVD drive if you want to use a Windows 7 installation disc to install Windows 7 on a netbook or other PC that doesn't have a DVD drive.
Your product key. You can find your product key on your computer or on the installation disc holder inside the Windows package—or in a confirmation e‑mail if you purchased and downloaded Windows 7 online. A product key sticker looks similar to this:
PRODUCT KEY: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
Go to the Microsoft website to see examples of product key stickers.
Your computer name, if your computer is currently connected to a network.
You also need to decide whether to install a 32-bit or 64-bit version of Windows 7. For help deciding, see 32-bit and 64-bit Windows: frequently asked questions.