Cubase Studio 5 Update

I have the original Cubase Studio 5 installed and registered.
I cannot update this product from 5.0.0 to the latest 5.3.3.
I have downloaded the updates and installed them on my PC but Cubase still runs 5.0.0
How do I get these updates installed into my program

Do you mean 5.3.3 or 5.5.3?

If you mean 5.5.3, you can’t go straight from 5.0.0 to 5.5.3.

You have to install the 5.5.0 update first.