Auto create Hyperlink to external file

[boylers75]

Hi,
not sure if this is possible. I want to automatically create a hyperlink in a cell where data is entered. In the attached sheet there are 2 columns, A with file numbers and B where a "Yes" can be typed if the file is present. What I want to do is enter a Yes, but have this automatically turn into a hyperlink using the file number in column A as part of the link to a .pdf of the same name.
Appreciate any help.