I admit to being not a computer geek. When anything gets updated does the update add on and improve whatever is being updated or is it a case of taking the place of the old version. What exactly happens when something is updated?

My computer runs better. Not a geek either.

My computer runs better. Not a geek either.Still have the question does an update always just add on and change whatever is being updated. Is there ever an old version of something that needs to be got rid of?

Yes.

It depends on what is being update and why. The normal Updates that Microsoft pushes out on Patch Tuesday are generally addons, but they may actually replace certain files. Many programs make use of a great number of files. For example, there may be several DLL (Dynamic Link Library) files. Each DLL has code that performs one or more functions. So lets say a bug was discovered in XYZ.DLL. Microsoft may just replace that file with a new one. Or another DLL, might actually be physically updated. The most common would be to replace the specific files that cover the functionality being patched or enhanced. But its not the whole program that is being replaced.

IN THEORY!

There are two primary reasons to release updates:

1) A bug (problem) has been identified within an application and a fix to that bug is being released and distributed.

2) Probably the most common reason now-a-days, a security window has been breached, hacked. The owner of the application or platform has identified the intruding program and plugged the hole. The update is a release to stop the invading villain.

In some cases a program is updated by a "Patch" where the parts of the program that are faulty are replaced, or a new function is added. However, many software vendors release new versions of the program to be installed over the existing, or uninstalled then reinstalled with the new version. In these cases (like with JAVA and Adobe) aside from user settings the update provides an entirely new platform. Sometimes, especially when program versions are very distant, the update can be installed alongside the original program. This is very common with commercial software.