I think it's more that the registry and filesystem get bloated and crufty. You can defrag an older installation and it'll still be slow. It happens on new syst

I think it's more that the registry and filesystem get bloated and crufty. You can defrag an older installation and it'll still be slow. It happens on new systems too. I've done it dozens of times, install Windows and be happy about the fresh, fast installation. Install some apps so you can use the machine and it slows down. Office was always the worst, even on a brand new install.