First off congratulations on choosing an awesome webcam!

/coughcoughbiasedcough
Now to the problem; technically it's fine to leave the webcam working on generic
drivers, it will still function exactly as it's supposed to. If you want the official Logitech ones though, along with the ability to use the software it comes with (allowing various special effects) then you need to get rid of those generic drivers.
In your Start menu,
right click on Computer and hit up
Manage. This will bring up the Computer Management window which you may or may not be familiar with. In the left hand pane toward the bottom you'll see
Device manager, go ahead 'n' click it.
The middle pane will now change to show all your currently installed and plugged in hardware, so make sure the webcam is plugged in for this step.
In
Imaging Devices you'll find Logitech HD Webcam 270,
right click and then click Uninstall.
Once it's finished up (should only take a few seconds), set about installing the Logitech drivers. Voila!