Found a blog post over at Link Removed
that explains how to install WinPCap, which is a very useful packet capturing library, on Windows 7. If you try to install WinPCap like a normal application on Windows 7, it fails.. Follow these steps to get the install to work..
Right click the downloaded installer exe and choose Properties
Go to the Compatibility tab
In Compatibility mode, Tick “Run this program in compatibility mode for:â€Â￾ and choose Windows Vista (Service Pack 2) from the drop-down
Tick “Run this program as an administratorâ€Â￾ in Privilege Level
Hit OK
Run the exe and go through the normal installation