Hi,
I recently encountered difficulties installing the latest NWC 2.75 previews on my Windows Vista.
Problem: When clicking the installation exe file, the hour-glass appeared for a few seconds, and then nothing happened.
After searching through various websites, I came across a fix for this:
1) Right-click on the exe file
2) Select Properties->General Tab
3) Where it says at the bottom "Security: This file came from another computer and might be blocked to help protect this computer." click on the Unblock button
4) Click on Apply, then Ok
5) Click on the installation exe file again
Problem Solved!
Regards,
Ian