My problem appeared for the first time in the summer when I updated NIS 2010 to NIS 2011. Since then the CPU usage of System process of Windows Vista 'peaks' up to ~50% for couple of seconds and then comes down. It does that quite many times in the day. But sometimes it doesn't 'come down' (one or two times in month). For example today I noticed that the System process had used ~50% of the CPU for over 40 minutes!
What could cause this? Could the NIS 2011 be the reason for this because the problem appeared for the first time after installing it? And how can I fix this?
So far I have just reset my computer because I'm afraid that it won't shut down using Windows because the ~50% CPU usage says to me that something is stuck.
Sorry for my bad English but I'm little stressed and starting to get tired of my computer. Maybe I should just buy a new one..