C cleaner
CCleaner (formerly Crap Cleaner) is a freeware system optimization and privacy tool. It removes unused and temporary files from your system - allowing Windows to run faster, more efficiently and giving you more hard disk space. The best part is that it's fast! (normally taking less than a second to run) and Free.
http://www.filehippo.com/download/fi...a39643ee8ba4d9
100% safe been using it for years
Spybot - Search & Destroy detects and removes spyware, a relatively new kind of threat not yet covered by common anti-virus applications. Spyware silently tracks your surfing behaviour to create a marketing profile for you that is transmitted without your knowledge to the compilers and sold to advertising companies. If you see new toolbars in your Internet Explorer that you haven't intentionally installed, if your browser crashes inexplicably, or if your home page has been "hijacked" (or changed without your knowledge), your computer is most probably infected with spyware. Even if you don't see the symptoms, your computer may be infected, because more and more spyware is emerging. Spybot-S&D is free, so there's no harm giving it a try to see if something has invaded your computer
The home of Spybot-S&D!
Again 100% safe
HijackThis lists the contents of key areas of the Registry and hard drive--areas that are used by both legitimate programmers and hijackers. The program is continually updated to detect and remove new hijacks. It does not target specific programs and URLs, only the methods used by hijackers to force you onto their sites.
Trend Micro HijackThis - Free software downloads and reviews - CNET Download.com
Just be carefull with this one