I used VB6 Pro before on my computer, but HDD crashed. What can I do?
Microsoft Visual Basic Professional Edition is not available anymore. Nowadays, there is another platform released by Microsoft and it's called Microsoft Visual Studio which has support for a wide number of programming languages. It's not possible to install the old version of the software you have mentioned.
New version's homepage: https://www.visualstudio.com/en-us/products/visual-studio-professional-with-msdn-vs.aspx
You might need to upgrade to something that's actively maintained and offers additional features.