Right click deletes instead of selecting in edit mode

I seem to have slipped and pressed something on the keyboard I didn’t want to and now I cant select verts, edges or faces with right click. When I press A to select all that works but right clicking deletes whatevers selected. Anyone know why? Blender version 2.70a

Use the latest blender version
File / Load Factory Settings, Save your settings
Restart blender
Use the default shortcut presets.