I have a lenovo laptop 512 mb ram 120 gb hard disk. It runs nicely but suddenly it shuts off but not always, it runs ok months after months. Main problem is that at the time of formatting it shuts off so many times and after trying many times OS can be loaded then it runs for some months, then again suddenly it shuts off. As shutting off does not maintain any time, any program or any sequence it is very problem to detect the problem. Even I have taken the laptop to the service engineer but that time it does not give any problem. I am using Quick heal antivirus and updated regularly. Please help me. Thanks
