Here is the suggestion from microsoft before upgrading from Windows Vista to Windows 7
Windows 7 Upgrade Advisor
Find out if your PC can run Windows 7
To see if your PC is ready for Windows 7, download the free Windows 7 Upgrade Advisor. It scans your PC for potential issues with your hardware, devices, and installed programs, and recommends what to do before you upgrade. (If you’re already running Windows 7, you can add premium features online with a
Windows 7 upgrade.)
The Windows 7 Upgrade Advisor checks for compatibility issues.
If your PC can run Windows Vista, it can probably run Windows 7, but it's still a good idea to download and run the Windows 7 Upgrade Advisor before you begin the upgrade process.
Note: Information about your PC will be sent to Microsoft, but no information will be used to identify or contact you. For more information, read the
Windows 7 Upgrade Advisor privacy statement.
Before you begin
Before scanning your PC with the Windows 7 Upgrade Advisor, be sure to plug in and turn on any USB devices or other devices, such as printers, external hard disks, and scanners, that you regularly use with the PC you're checking.
Download the Windows 7 Upgrade Advisor