Search not launching apps

Hi everyone,

I've recently come across an issue whereby if I hit the start key and start typing the name of an app it no longer launches once I hit the enter key. This was the easiest way for me to launch apps without cluttering up the interface with icons, and I don't understand what could have changed? The app will be highlighted on the menu but nothing will happen. It still launches using the mouse, however. Ideally I'd love to be able to fix this rather than relying on a third party app such as Launchy or Classic Shell.

If anyone has a solution I would be more than grateful.

Thanks!