Problem with security cert when going to checkout or clicking on contact

[Dave L]

Hi Guys,

Appreciate if anyone could help.

On my site www.morris-trading.co.uk if you click on Contact or go to checkout after adding to cart I get the "There is a problem with this website's security certificate." message in Explorer 7

I have read lots of threads but can't seem to find a solution.

I'm using V1.3.1.1

Advice appreciated.

Dave.