Vistro 1500 Freezes

After receiving Dell repair of hinge (DPS Reference#000109143251 dated 11/4/2008) under warranty, freezing of screen started. Lately, we reinstalled Windows Vista Basic, tried to update Windows. It installed some of the updates. While installing Norton Virus 2010, the laptop froze before completing the installation.By pressing  ctrl+Alt+Esc Keys, no response. Tried to push and hold power botton, it will not turn off. Finally, we had to take out the battery in order to turn off the laptop. Now it does not boot up. Same thing has been happening as it did after receiving back from Dell after servicing hinge.It is very frustrating to see that a reputable company like Dell is making such product that cannot be relied by loyal customers like us. We hope Dell takes freezing problem and get at the bottom of it and help find solution to freezing problem. We are requesting Mr. Michael Dell, CEO, to personally look into it.There has been many cases like this with Vistro 1500 as posted on Dell Community. If Toyota could take steps to solve brake and other problems in its automobiles for its reputation, we hope that Dell considers doing the same to solve chronical Vistro 1500 freezing problem to protect its reputation as well.Thanks.