My intel pentium dual core 2.10 Ghz laptop having 3 gb ddr3 ram gets shut down without overheating while playing games,antivirus scans and during running heavy programs.i have cleaned heat sink and i don't think that overheating is causing this problem......my cpu temp remains 45 c to 50 c.and i also tried to reinstall windows 7 but during installation it shuts down i tried to run memtester but system shuts down......what should i do please help me.....