Remove apps you no longer need: Revo Uninstaller (free), our favorite app uninstaller for Windows, completely deletes every trace of a program with just a few clicks.
Clean out the junk files: The speedy Ccleaner will banish temporary files, log files, and other space-hogging stuff you don't want on your new Windows 8 system.
Defrag your drive: Even though we don't generally recommend defragging Windows Vista or Windows 7 PCs because they are already configured to defragment your drives, it's a good idea to check if your drive actually has been defragmented. By default, the defrag runs at 1 am every Wednesday, so if your computer isn't on at that time, it might not actually be defragged. While the built-in defragmenter is fine, a third-party tool like Piriform's Defraggler offers more features. Also note that if you have a SSD, you do not want to defragment.