Make a backup of your config, then give this one a try
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0"
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
EndSection
Section "Files"
EndSection
Section "Module"
Load "dbe"
Load "extmod"
Load "type1"
Load "freetype"
Load "glx"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
# generated from default
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "Unknown"
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
Option "TripleBuffer" "On"
Option "ConnectToAcpid" "Off"
Option "metamodes" "nvidia-auto-select +0+0 {ForceCompositionPipeline = On}
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Extensions"
Option "COMPOSITE" "Enable"
EndSection
Section "InputClass"
Identifier "Keyboard Defaults"
MatchIsKeyboard "yes"
Option "XkbOptions" "terminate:ctrl_alt_bksp"
EndSection
and also create the kwin.sh as described here:
Also, if you want a fixed layout instead, see the second example of the config i provided there, as an example.