Outlook Problems

HI all

hopefully someone can help me solve a problem i am having.

On my laptop, when i try to open an email (one that is already in my inbox), i double click on the message and then the system will often sit waiting for something, the little symbol in the top left hand corner goes white, and i cant do anything for up to 4 or 5 seconds.

Then the system recovers itself and i can work as normal.

Next message, does the same thing.

Any ideas how i can find what is holding the system up ??