Our product, Integrity Master checks and, if necessary, reloads this data. Be sure to check that your program can handle the new larger CMOS memories found on almost all newer PCs made since 1992. Today many viruses actually go out of their way to avoid infecting this file, since some anti-virus products single out this file and a few others for special scrutiny. While it's helpful to check the file size or the time and date stamps of your executable files for unexpected changes, this is not a reliable way to catch viruses. Many viruses are smart enough not to change the time and date stamps when they infect a file.
Some viruses even hide the change to a file's size when they infect a file.
Many products make claims which they can't support. Everyone would like to just buy product X, run it, and be rid of viruses forever. Unfortunately there is no such easy cure. It's important to understand how your anti-virus software works and to understand its weaknesses. This is also true on networks.