Thanks for the question brooksbycb. Security is always a worry and I am afraid that there is little I can say to offer reassurance on this specific issue. There are some precautions that I take regarding security checks and this is covered here:
http://www.excelcalcs.com/frequently-asked-questions/excelcalcs-faqs/virus-threats/
I hope that this reassures you a little butI would be glad to hear from any users who can advise of other actions or good practise to minimise security risks from ExcelCalcs downloads.