Have used Bitdefender for several years now. Previously i have used Norton and McAfee - both allowed infections to sneak by and crashed computers I have owned. Have not had an infection since changing to Bitdefender. My only complaint is on my wife's Vaio that on rare occasions freezes with a blue-screen, in deciphering the code its related to BitDefender - per some forum posts i uncovered. Its not a big issue since a reboot clears it - a small price to pay for great protection - and its only on the Sony Vaio - two Dells and a Lenovo are fine with the program.