Watch this video: https://youtu.be/AOLu1v5NeJ0 for a video tutorial! :)
Before starting an upgrade, make sure you're following the correct 'Upgrade Path' from Windows XP or Vista to Windows 7.
You must also make sure you're purchasing the correct 'Bit' version 32bit or 64bit as upgrading from a 32bit > 64 bit or vice versa isn't supported.
IMPORTANT: Always make sure to backup your personal data just-in-case, even when doing upgrades, as errors can occur.
Windows USB DVD Download TOOL BELOW;
NOTE: When you download the ISO file, you must copy the file onto a USB flash drive or a DVD to install Windows 7. When you’re ready to install Windows 7, insert the USB flash drive into your USB port or insert your DVD into your DVD drive, and then run Setup.exe from the root folder on the drive.
The advantage to following this process and creating bootable media is that it allows you to install Windows 7 without having to first run an existing operating system on your machine. If you change the boot order of drives in your computer’s BIOS, you can run the Windows 7 installation directly from your USB flash drive or from a DVD when you first turn your computer on. (Please see the documentation for your computer for information about how to change the BIOS boot order of drives.)
To install the Windows 7 USB/DVD Download tool:
1. Click to open the Windows 7 USB/DVD Download tool installation file.
2. When you are prompted to either save the file to disk or run it, choose Run.
3. Follow the steps in the setup dialogs. You’ll have the option to specify where to install the Windows 7 USB/DVD Download Tool.
NOTE: You need to be an administrator on the computer you are installing the Windows 7 USB/DVD Download tool on. The tool requires the Microsoft .NET Framework version 2.0 or higher.
Windows XP SP2, Windows Vista, or Windows 7 (32-bit or 64-bit)
Pentium 233-megahertz (MHz) processor or faster (300 MHz is recommended)
50MB of free space on your hard drive
DVD-R drive or 4GB removable USB flash drive
Once the USB/DVD-TOOL creates your media, navigate and open that USB or DVD to view the files inside the folder. Next follow these instructions once you double click on Setup.exe;
1. Click on "Install now"
2. Click on "Go online to get the latest updates." Doing so will result in a better install experience. (Important! If updates don't process after a couple of hours, restart the process, and check "Do not get the latest updates for the installation")
3. Accept the EULA (end user license agreement).
4. Choose Upgrade from the installation type screen.
5. Setup will alert you if any currently installed applications are incompatible with Windows 7 and, in some cases, recommend reinstalling these applications after the upgrade for best results. If Vista is waiting on a Windows Update-based reboot, for example, Setup will halt and inform you to reboot before trying again.
6. Once you're done with the Compatibility Report, you'll be confronted with the familiar Install Windows phase of Setup.
7. Once setup is done upgrading, your computer will boot to your freshly upgraded Windows 7.