I use Kaspersky Anti-Virus 1 position for years, it does not slow the computer and runs in the background without problems, the updates are automatic. He always detected malware and others before they settle, including peripherals (USB key) with locking options and / or automatic repair. Unlike a provider of anti-virus, as "residential" also protects the machine and not just the connection. Tip: I buy and reinstalls every year because I noticed that it is cheaper than an online subscription renewal.