Left/Right Click

I have been unable to left or right click on objects in world. As a result, I am unable to teleport, sit down, open my pie menu to change appearance, etc. I am working with windows XP and SL worked until my motherboard was replaced. My mouse works fine for my huds, chat windows and everywhere outside of SL. Any ideas how to fix this?

This issue continues to persist after formatting harddrive and reinstalling windows and all drivers. The mouse works correctly in everything but second life, including the second life beta version. Prior to motherboard installation, everything worked fine in second life. I've messages linden's about this and only received standard reply. Have heard nothing back after advising linden's that problem persists after their suggestion. Please, any ideas on this issue would be great help.