There are 3 major dependencies although these are handled automatically by the DS Mechanical install utility:
1. You need to be running the latest .NET framework; keeping the Windows Update switched on keeps it at the most current version.
To install it manually, visit the Microsoft website for details: https://www.microsoft.com/net/download
If installing DS Mechanical 4.0 on a Windows 7 64-bit computer, you need to have .NET Framework 4.6.2 installed:
2. Java: The latest version is required. Download at https://java.com/en/download/manual.jsp
Make sure to have 32-bit Java for a 32-bit DS Mechanical install or a 64-bit Java for the 64-bit DS Mechanical file.
3. Microsoft Visual C++ Redistributables: Most of these should be automatically installed by Windows for use with other programs. But, check that you have at least the x86 or x64 version of each of these yearly updates to the Redistributables (2010, 2012, 2013, 2015).
Download links for VC++ here: https://support.microsoft.com/en-gb/help/2977003/the-latest-supported-visual-c-downloads