Hi Paul,
First of all go the FAQ section of the website (
https://www.swisslogforwindows.com/faq.html) and follow all the steps explained in "Swisslog is not launching at all". Also make sure you have added exception to the Swisslog folder in your antivirus and allow all incoming/outgoing communications in your firewall to the Swisslog executable file.
If all this fails, is only Swisslog affected or you have similar problems in other software? If this is the case then it could a virus. I highly suggest you to restore your system to a previous date where all worked. It's the faster and safer method to restore your system back to normal.
Please let me know if all works after you have applied what it's explained in the FAQ and added exceptions.
73