It is advisable to plug in any USB devices or other devices such as printers, external hard drives, or scanners that you regularly use so that the compatibility of such external devices can also be analyzed.It also suggest any driver upgrades if required and can be downloaded from Windows 7 Update.
System Requirements for Windows 7:
- 1 GHz or faster 32-bit (x86) or 64-bit (x64) processor
- 1GB RAM (32-bit) / 2GB RAM (64-bit)
- 16GB available disk space (32-bit) / 20GB (64-bit)
- DirectX® 9 graphics processor with WDDM (Windows Display Driver Model) 1.0 or higher driver
The Windows 7 Upgrade Advisor is compatible with Windows 7, Windows Vista and Windows XP.
Windows 7 upgrade Advisor is free and is only available in English.
Download : Windows 7 upgrade Advisor
Source : Windows Experience Blog