2. On CCleaner (under Custom Clean) use the following options:
Windows and Applications Cleaner (uncheck any item you find unnecessary)
Under Tools use the Uninstall option to remove unnecessary programs
Under Tools use the Startup option to disable unnecessary Startup entries
Under Tools use the Browser Plugins option to disable any unwanted or risky add ons/extensions/plugins
Under Registry option scan for issues and once it is done finding them, use Fix option to remove registry errors, but make sure to backup the entries--CCleaner will give the option to do so run this program every day after your work is done on your PC
3. Run a defrag using Disk Defragmenter from the hard drive/ C: Drive Properties dialog box at least once a month (the process can take some time to finish).
4. Run a Threat Scan using free version of Malwarebytes Anti-Malware. Make sure you enable the ‘scan for rootkits’ option under Settings-->Detection and Protection and quarantine any threats (make sure you do not enable the trial version unless you plan to buy it). Run Malwarebytes Quick Scan on a weekly basis.