NIS 20.4.0.40 Won't Scan

Hi

 

For some reason unbeknown to me my NIS 20.4.0.40 will not scan my Computer.  When I click on Perform Full System Scan or if I click on Quick Scan, nothing happens, literally nothing.  It's as if though I am clicking on a dead link.  If I click on Custom Scan I am taken to a page where I can select various scans but if if I click Full Scan on this page it just goes back to the scan selection front page and nothing else happens.

 

My last successful scan was 3 weeks ago.  I have made no changes to my computer which is running Windows 8.

 

Please advise.

 

Thank you.