You will need to clean all unneeded files from your system so that you can gain some speed and disk space. The first screen you will see when you open CCleaner is the Cleaner screen. This is where you will select all the types of files that you want CCleaner to find and eliminate them. There are two buttons on the bottom the left most is to analyse your system to list the files that CCleaner will want to delete. After CCleaner list these files you will still need to use the right most button to clean your system of the listed files. The right most button will find and delete the files at once.

The next step is not exactly for novices, if you do not know the names of files in your system that you should be run on startup. This is where most viruses / spyware / malware will infect your system. They will startup automatically each time you restart your computer and be running all the time. If you are savvy enough you can disable files that are not needed and files that should not be run so that cleaning your systems of threats is much easier. If you are not savvy enough just disable everything and Windows will automatically re-enable anything it deems necessary for it to run. You will need to restart your system to complete this phase of cleaning.

CCleaner has more functionality but these two steps will go a long way to improving your system speed and availability. This should be used first in your virus / malware hunt. After completing this you should run your Anti-Virus / Spyware / Malware software to eliminate threats.