Omsi.exe - Unable to Locate Component

The following message appears when I try to start OMSI.

This application has failed to start because d3dx9_28.dll was not found. Re-installing the application may fix this problem.

I cannot find previous threads on this. What do I do next please?

Yo don't have Microsoft DirectX9 on your Computer. Install it, and OMSI should work.

Many thanks!