Unless a security app runs real time scans, in other words, when data is coming into the computer (like when you’re browsing, or when you play a CD, or open an email and such) . . . you really don’t need to have it running at start up. Since it’s not protecting you in real time, it’s pretty much a useless drain on start up resources. It will only spring into action when YOU do an “on demand” scan (which some feel is like closing the barn door after the horse got out). On demand scanning is a user activated scan of the computer.

Phrasing for real time scanning may be more recognized as “real time protection” or “on access scanning” or “resident shield” (most antivirus programs use that terminology).

While most, if not all, free antivirus programs offer real time scanning (“resident shield”) AND “on demand” scanning, a lot of other free versions of security apps DO NOT offer on access scanning. For example, the free versions of most (but not all) spyware apps are “on demand” ONLY. It is these apps that you really don’t need to have running at start up.

To get the “on access” scanning capability, generally there is a “Pro” version that is retail. These are the ones that are good to have running at start up and protecting you in the background as you surf and open or download files.

While you do have to pay for most “real time” scanning capabilities, with the notable exception of free antivirus programs, the cost benefit analysis generally favors real time scanning programs. Better to catch the bad guy before he breaks into the house. Once he’s in, an on-demand scan may identify the culprit, but he’s hard to get out.