For the last couple months I’ve been troubleshooting a vexing problem on my new quad-core HP desktop: Roughly once per week, the machine would start running as slow as molasses. And I mean slow: ...

Q. Often when I go to defrag my computer, I have to analyze the drive first to see if it needs to be defragged. Most of the time it says it doesn’t need to be. Is it OK to defrag anyway? Will it hurt ...