i bought a new acer aspire 5722-6607 laptop in october 2011. a month after i got it it started overheating and shutting down. i got an external cooling fan it didn't do it for a lttle while. i sent it in to the company in dec 2011 for repairs. they company replaced the wieless internet card cause it was dropping the internet. they were to suppose to fix the overheating problem but didn't fix the problem the cleaned the cooling fan said there was ome debri in the fan. after i got it back it has been doing this off and on overheating and shutting completely down what is causing this?