A computer virus is a program capable of replicating itself. Viruses copy themselves and infect a computer without signaling the owner. Previously, viruses were one of its kinds; they could spread from one PC to another only through some means. But now there are a number of varieties in them, such as Malware, Spyware, Trojan, Worms, Adwares, etc. I suggest that you should be in touch with a Computer Support and seek advice from experts for preventing your computer from various issues.