Scheduling Scans
Having your antivirus program scan the entire computer for viruses is a necessity. Even though most antivirus programs have an auto-protect feature that should - theoretically - prevent the insertion of a virus onto your computer, it is still a good idea to scan your computer periodically in the event something was missed somehow by the automatic protection.
When to scan
When scheduling periodic scans, choose a day and time when you know your computer will be running. It is no good to schedule a scan for Friday night at 10:00 p.m. if your computer is turned off. The antivirus program will not wake up your computer if it is not running - but if it is already running, then it does not need to be awakened.
If your computer is in standby or hibernation mode (common battery-saving modes on laptops), your antivirus program will not wake it up to scan. It is got to be fully awake and running at the appointed time. On the plus side, your monitor need not be on.
One other factor to take into account for your weekly scan: Run it when your computer is running but when you're not using it. If you have one of those high-speed Internet connections (such as cable or DSL), then perhaps you keep your computer on all the time anyway. If so, then you can just schedule your scan to take place, say, on Fridays at 1:00 a.m. (or whenever you sre routinely not using the computer).
Manual or automatic?
If you turn your computer off when you are not using it, then you may need to change your habits a little bit - if you can get beyond the hassle - so the scan can run when you are not using the computer.
But why make a fuss about running a virus scan when you are not using the computer? Well, the computer needs all its resources to do the scan efficiently. If you are using your computer for just about anything else while a virus scan is running, it is generally not a fun experience. A virus scan makes your computer dog-slow, miserably-slow, because the scanning program has to examine each of the 20,000-50,000 files on your computer, checking every one for any of the 60,000+ known viruses. That is a lot of work for the computer to do.
If your computer is generally turned on only while you are using it (and only then), you have a choice to make: Either you need to scan the computer while you are using it, or you need to change your work habits to accommodate the scan. For instance, turn on your computer first thing in the morning, and run the virus scan while you are off taking a shower, eating a meal, meeting with other people, practicing the accordion, or whatever. Or run the scan at some other time when the computer is on but you are not using it for anything but the scan.
What to scan
Thankfully, figuring out what to scan is easier than knowing when to scan. Here is what this means: The antivirus program can be configured to scan different types of files. A file's type is determined by the last three letters of the file's name. For example, the file scanlog.txt is a text file, because the last three letters of the file's name (called its extension) are txt, meaning text file. A file ending in .EXE is a program - or executable - file, and a file ending in .CAB is a cabinet file, a special kind of archive file used by Windows.
There are dozens - even hundreds or thousands - of file types in use today. But the good news is that you don't need to know all these different file types. Why? Simple: The best thing is to scan all types of files! That is right: If you scan every type of file that there is now, or ever will be in the future, then you are 100 percent covered.
Fortunately, most antivirus programs do this comprehensive scan by default, but they still give you a choice. This is because a long time ago in a galaxy far, far away, viruses only infected .EXE and .COM file types, so scanning only those was all you needed to do. But then other types of viruses came along, and you had to scan more and more types of files, until the antivirus program makers got smart and added the option, scan all types of files. So this option to specify which types of file to scan is sort of a leftover from those earlier days.
You can, however, also tell your antivirus program which types of files not to scan - an exclusion list. But for the vast majority of readers, you do not need to tell your antivirus program which types of files to skip. You can just leave this blank.