i am using legitimate win 7 ultimate x32 bit OEM edition which came pre installed with my pc. and i installed all updates upto today. my question is when i am surfing for more than 2 hours my pc got 100% cpu usage when i check my task manager one process called system is running and using more than 80% cpu resources and description says windows nt kernel if i kill that process then also it is running in background for more than 15 minutes. in that meantime everything in my desktop flicks and hangs as well as i can't use my computer for that particular time i have to leave my pc idle. after 15 minutes or so everything backs to normal. my biggest surprise is i am only seeing these thing or this thing is common. so please anybody can clarify my doubt please.