The Microsoft Application Compatibility Toolkit (ACT) version 5.5 contains the necessary tools and documentation to evaluate and mitigate application compatibility issues before deploying Windows 7, Windows Vista, a Windows Update, or a new version of Windows Internet Explorer in your environment.
ACT helps customers lower their costs for application compatibility testing, prioritize their applications, and deploy Windows more quickly.
You can use the ACT features to:
You can get the tool from here.
Further information on the Windows Application Compatibility page on TechNet.