Q: I just purchased 'pages' but clicking the install button doesn't start the installation.

Hi ...

Try here >  Mac App Store: App purchase doesn't appear to complete

Ok...

If you have anti virus software installed, disable that.

Turn off the Firewall in System Preferences > Security & Privacy

If you have any apps like Little Snitch or Growl installed, either one can prevent apps from installing.

If none of the above apply ...

Install the OS X Lion Update 10.7.3 (Client Combo)

Then restart your Mac. That will reinstall the App Store for you which may help. It's ok to do this even though you are already running v10.7.3.

Then try re downloading Pages.

Open the App Store. From the menu bar click Store > Sign In

Click Purchases from the top of the App Store window.

Select which apps you want to re download. Then right or control click where you see Installed  then click Install.

Make sure and use the same Apple ID used for the original purchase.

edited by:  cs