1. There is some program running in the background (might even be the screen saver) that does something with the disk. You've got the choice between (a) find out which program it is, disable it before defrag, and enable it afterwards, or (b) boot into safe mode so that the program isn't started. It is interesting to start with #a, because it might be some malware you don't even know that is running.
2. No need to defrag every week. Only defrag after creating or extending many files larger than 1 block. The file system is designed to handle non-contiguous files, and does it very well.
Could someone be so kind as to tell me how I can get my computer to defrag. It use to every Thursday night but know it has a hard time getting to 7 percent let alone completing the task. it says " drive content change" I was able to defrag in safe mode but I would rather fix the problem then to do that every week
thanks in advance