I’m thinking the lack of updates may be causing the corruption issue, but again, I thought I needed to get an anti-virus program loaded first before running Windows Update (or doing any extensive online work).Antivirus programs are powerful pieces of software that are essential on Windows computers.Most antivirus programs set up scheduled full system scans, often once a week.This ensures that the latest virus definition files are used to scan your system for dormant viruses.However, you don’t usually have to run full system scans yourself when an antivirus program is already protecting you – it’s always scanning in the background and doing its own, regular, full-system scans.Your antivirus software relies on virus definitions to detect malware.Full-system scans can be useful for some things, however.
Your antivirus software checks the program first, comparing it to known viruses, worms, and other types of malware.
Your antivirus software also does “heuristic” checking, checking programs for types of bad behavior that may indicate a new, unknown virus.
Antivirus programs also scan other types of files that can contain viruses.
Antivirus labs use a variety of tools to disassemble viruses, run them in sandboxes, and release timely updates that ensure users are protected from the new piece of malware. Heuristics allow an antivirus program to identify new or modified types of malware, even without virus definition files.
For example, if an antivirus program notices that a program running on your system is trying to open every EXE file on your system, infecting it by writing a copy of the original program into it, the antivirus program can detect this program as a new, unknown type of virus. Heuristics can’t be too aggressive or they’ll flag legitimate software as viruses.
Because of the large amount of software out there, it’s possible that antivirus programs may occasionally say a file is a virus when it’s actually a completely safe file.