After you have gathered some initial information about the amount of fragmentation on your drive, it is time to perform a defragmentation pass. There are two types of defragmentation pass that you can choose from: Online and Boot Time (Offline). Online defragmentation is performed immediately by analyzing your drive. However, certain files such as system files, pagefile, and certain directories, etc. cannot be defragmented while Windows is running. It requires the machine to be shutdown when you want to defragment those files. This is called Offline or Boot Time defragmentation.
Choose to learn more about the two types of defragmentation on your system:
§ Boot Time or Offline (System Files Only) Defragmentation
Both of these types of Defragmentation types can be run using the following three methods:
§ Manually (Immediately running a defragmentation)
§ Schedule to run automatically (Discussed in detail in the Scheduling Defragmentation section
§ Preventing fragmentation using the Automatic Modes defragmentation methods: OptiWrite, StealthPatrol, & Screen Saver