Hello Everybody, I'll be typing in some detailed description so please read this only if you're a sincere helper and have patience for newbies. I have a Dell Laptop and I have been working on it for many long years. It is a Dell laptop + I handle my gadgets very gently ; so it never gave me any trouble. Till yesterday midnight everything was fine. While I was just searching for a file in my folders on Windows Vista using windows explorer, the laptop switched itself off today just after my one click (this must've been of the order of 100th or 300th click of mine today). Please let me explain what I mean by "switch off". There are (at least) two ways a computer can turn off. First is to use the shutdown command in the OS and see the programs close, then the userprofile logout and then OS close and then the computer "turn off". Other is to just press the POWER BUTTON and see the computer "turn off" directly, I.e. improperly. I never do the second activity but very very rarely (once in 5 weeks) I do so if my laptop's vista OS hangs due to some CD or internet or anything... This kind of improper turn off is what I mean by "switch off". I don't know what it is that causes the sound but whenever I switch off my laptop I hear a sound of something. I guess it is a plug or something inside the laptop with some role in laptop's function. So when my laptop switched itself off today (Aug-11,'16) in the morning (07:00 A.M. (GMT+5.5hrs)) I heard that sound too. I thought the laptop was hot and that made the laptop switch off itself. This used to happen once in twenty days or so earlier even. I returned an hour or half after that time and took off the keyboard usb plug and cleaned the laptop using a cloth. I even blew air on the fans and air flux gaps and could see and feel dust coming out. I continued until the clear end of this process of dust coming out. When I turned on the laptop things went really well for fifteen minutes or so. And then the laptop switched itself off once again. This time the case was a bit different. It was very gradual. First the computer slowed down, then it hanged and then the screen went blank and THEN the laptop switched itself off. I'm quite confident that this is an over-heating issue. I read on the internet and saw five or so reasons for this. I don't presently think that mine is an issue of virus or erroneous power supply. As a matter of fact, I never in the past four years serviced my laptop by getting it opened and cleaned by an expert PC technician who services laptops. I was curious if someone could suggest me how or just suggest me a book to find out how one can service his laptop as I won't prefer to have someone else handle it. I won't prefer because maybe he'll create a new problem deliberately just to have me visit him again and again. I don't like maintenance contract people and have successfully worked on my laptop for the past four years without having any technician touch it, open it or diagnose it. Please let me know even if you believe my way is wrong and I should put my faith in a technician and get my laptop serviced. It is a Dell studio 1537 laptop (Core2duo 4GB ram) and I had purchased it in 2008. Its warranty expired in 2012. Thanks for your spending time on this long help-seeking essay And yes, thanks for whatever you may suggest me. Truly, Gunjan Garg, Gautam Buddha Nagar, India.