After trying several free and sharewares antiviruses, for short while staying in that condition before buying one, I stayed with free AVG 7.5 whose exe I had. I had used it a long while (it's "516 a 1225") but got sick with the rumour that it will disappear. I have installed and uninstalled NOD 32, Avira, Avasta, etc. I have XP Pro; huge hard disk space; 1 G RAM; old Pentium III/700, functioning pretty well (sorry for I live in a the "underdevelopped" world where middle class is poor). I am very cautious in its cleaning, defrag and so on. Well, since the last AVG install, I get every other day uninstallation of resident shield... It's random, what makes the trouble very rare. And also a headache, for I have a lot of work to do and little time, and having to restart every time I go to my PC is a very "nice" way to start the day. I appreciate if somebody could help me. Many thanks and friendly greetings.