In my windows 7 home premium, several of my application crashes after some minutes even wehn I am not touching system. For example I have outlook 2007, that works fine, but suddenly crashes. The same about visual studio 2012. It is also crashes after some minute no matter if I am working on a project or I am not touching it. the same behaviour is there, for other applications (skype, oovoo and ...). I use Microsoft security essential and there is no virus on my system. I also checked my system with Sophos anti root kit and there is no root kit there. What would be the problem?