Here is a quick way to know if a binary file (*.exe, *.dll, *.ocx, …) has a dependency on the Visual Basic 6.0 Runtime. The trick is to use the Dependency Walker tool to see its dependencies. The dependency you are looking for is the Visual Basic 6.0 runtime library (msvbvm60.dll), and it appears on the tree if you are dealing with a VB6.0 binary:

If you are concerned about the VB6.0 runtime not being supported after Windows Server 2008 and Windows 7, this is a trick that can help you decide whether to keep a particular third party ActiveX component in your application through COM Interop after migrating to the .NET Framework or to start looking for a replacement in case the runtime is no longer available (and thus the component will no longer work).

Dependency Walker is a freeware tool that was included with Visual Studio 6.0, is included in the Windows Support Tools and can be downloaded from the Dependency Walker homepage.