D620 - DUAL CORE function

Hi, following many freezing problems on this particular Model (The ones with Dual Core processors) We have decided to deactivate the DUAL CORE function in the D620 Bios settings. We have also tried to patch the Windows OS PC with the KB896256-v4-x86-ENU.exe You can find it here : http://support.microsoft.com/?id=896256 Then we re enabled the DUAL CORE setting. => But the freezing went back after 2-3 days of use. Anyone having problems / freezing effects using a D620 with tht DUAL CORE setting turn on ? Has DELL got a Patch for the D620 DUAL CORE Processors ? Thanks, Martin