Hi,
to help you best we need to see the actual dump files. As your machine isn't creating them please make sure your settings are set like thus:
Open the run application.
Type sysdm.cpl in the run box and click ok.
Look across the top of the system properties box for 'Advanced' and click that.
Look for 'Startup and Recovery' near the bottom and click 'settings'.
Near the bottom you'll see a drop down menu under the heading 'write debugging information'.
In the drop down menu choose ' small memory dump (256KB)'
Under 'small dump directory' make sure it says %SystemRoot%\Minidump.
Click ok and your good to go.
Other reasons for no dump file can include no pagefile or one that's below 200mb so if you changed it return to default values...