You need to add "HWCursor" "Off" to your Device section.
Section "Device"
Identifier "Default Device"
Driver "nvidia"
Option "UseEvents" "1"
Option "DPI" "100x100"
Option "NoLogo" "1"
Option "HWCursor" "Off"
Option "IgnoreEDID" "On"
Option "NoDDC" "On"
Option "TripleBuffer" "True"
EndSection
Regards
Ian