VirusBarrier Express

So today I downloaded Virus Barrier Express. After downloading, my Mac became unresponsive; I began to get the spinning beach ball every time I tries to use a program/internet. At first I thought it was because it was still installing virus definitions. After those were finished, I proceeded to scan my mac, and it scanned without problem. After finishing however, my mac was still unresponsive with the spinning beach ball appearing as I tried to use a program/internet.