Defragmentation rearranges data on a disk so that it is stored sequentially rather than randomly. This decreases total access times. A computer system becomes fragmented when files are stored in a non-contiguous manner on the disk drive. In other words, rather than being stored as a complete unit in adjacent disk segments, files are stored in a "broken up" fashion or with gaps. The Defrag process first involves analyzing your system to see if it needs defragmentation. If the system requires it, the program proceeds to physically organize the disk content so that various section of each file are more contiguous and saved closer together.
A process is a task initiated by software programs. It is like information passed in an envelope that includes instructions and data for the program such as current activity, task number, and actual program code. In some cases, one or more processes can seize the computer or perform malicious activities. This can result in the entire system functioning incorrectly.
The registry is a key component of the Windows operating system. Without it, Windows would not be able to run. The registry contains information and settings for all the hardware, software, users, and preferences of the computer. The operating system continually references this information during its operation. When the registry becomes very large, the computer's performance can decrease and may cause it to be unstable. Note: Making changes to the registry can cause damage to your system. You need to proceed cautiously and be certain of what you are doing.
A restore point is a "placeholder" on Windows operating systems that enables you to revert your computer operations to a previous point in time. Windows creates restore points when performing an update to the system and when it is scheduled. Applications can also create restore points at the point of install or uninstall.