Drag steals clock-cycles from your processes so that it can run in a higher priority mode. Anti-virus software especially places a drag on your computer. Depending on your settings (and the default settings are usually very aggressive), every time you run a program or open a file, real-time file scanning takes place and your files are scanned for viruses. This slows down your processing. Accessing larger files takes longer. You can see a discernible lag time between when you start a program/open a file and when you can actually access it.

After the obvious issue of “drag” is compatibility. Often security and anti-virus rules get in the way of your doing business on your computer. While you may get away with using older versions of such packages as Word, Sims, Photoshop, etc. on your computer with the new XP operating system, it’s unlikely your security software will be completely compatible. Why? Many packages rely on very low-level functionality to be able to do the tasks they set out to do. Anti-virus packages have to be able to operate at a level closer to the hardware than most packages. They need to do this to prevent virus software from taking precedence from them. While many packages offer backward-compatibility the opposite is not true: forward-compatibility. There are several reasons for this: a package written for Windows 98 will not anticipate all the changes to the operating system that are implemented for Windows XP. While your Win98 anti-virus program may work under XP, it won’t work at its peak performance