To clean up unnecessary startup items, launch CCleaner and click the Tools icon in the left margin. On the resulting screen, click the Startup button; you'll see a number of tabs for Windows and any browsers you've got installed. The Windows tab lists all of the programs that start with the OS, while the tabs for the browsers list any add-ons that launch automatically. If you're unsure about which items can be safely disabled or deleted, do a Google search with the file name to find out what it does and if you need it. Odds are, most items can be safely removed, save for any security apps or apps that run scheduled tasks. In our example screenshot, everything can be safely removed except for the AVAST Software entry.
Optimize and defragment
After updating your system and removing any junk data and malware, it's always a good idea to run a disk defragmenter to minimize file fragmentation and improve the perceived performance of your hard drive. To defrag a drive, right-click on it in File Explorer and then choose Properties from the menu. Click the Tools tab in the window that pops up, and then click the Defragment now (Windows 7) or Optimize (Windows 8) button to launch Window's built-in defragmentation tool. Once the defragmentation tool opens, highlight your hard drive and start the defragmentation process.
Please note that you should never run a disk defragmentation tool on a solid-state drive. SSDs are not affected by file fragmentation in the same way as hard drives are and don't need to be defragged. (In fact, defragging SSDs actually shortens their lifespan.) Most modern SSDs have idle garbage collection or a feature called TRIM that will optimize free space when a system is idle. After purging a bunch of data from an SSD, it's a good idea to restart your system and just let it sit idle for a while to let the SSD do its thing.