CCleaner is best and most reputable Registry Cleaner. Period. Powerful scan engine, regular updates, lots of additional features and excellent price of FREE makes it the best. You may have already heard about it a lot, but if you can’t find it installed on your PC download and install it right now!
BitDefender Antivirus – one of the best antiviruses in last couple of years. Doing greatly in all tests. Interface and speed are on the highest level. Here you have an opportunity to get one of the best antiviruses on the market.
Malwarebytes Anti-Malware – relatively new project, but already became one of the leaders of antimalware and antispyware industry. The key to its success is obvious – simple interface, great database, speed, and super effectiveness in fighting against modern threats. Software has free version, but you can buy module of active protection.
SpyHunter – very powerfull antimalware for additional PC protection, has very specific database that allows to detect threats that cannot be detected by “classic” antiviruses. Can detect adware browser extensions, hijackers, keyloggers, trojans, worms, rootkits.