Trackpad issue with 2010 MacBook Pro
First try to restart the computer. 

If the keyboard still responds try to get to terminal from quick search. (cmd space normally)

in terminal you can try to change the preferences via the command "defaults"
the folling command outputs the various settings.

defaults read com.apple.driver.AppleBluetoothMultitouch.trackpad


The output for me is here. 1 means active (or true), 0 means not ative (or false). 

{
    Clicking = 1;
    DragLock = 0;
    Dragging = 0;
    TrackpadCornerSecondaryClick = 0;
    TrackpadFiveFingerPinchGesture = 2;
    TrackpadFourFingerHorizSwipeGesture = 2;
    TrackpadFourFingerPinchGesture = 2;
    TrackpadFourFingerVertSwipeGesture = 2;
    TrackpadHandResting = 1;
    TrackpadHorizScroll = 1;
    TrackpadMomentumScroll = 1;
    TrackpadPinch = 1;
    TrackpadRightClick = 1;
    TrackpadRotate = 1;
    TrackpadScroll = 1;
    TrackpadThreeFingerDrag = 0;
    TrackpadThreeFingerHorizSwipeGesture = 2;
    TrackpadThreeFingerTapGesture = 0;
    TrackpadThreeFingerVertSwipeGesture = 0;
    TrackpadTwoFingerDoubleTapGesture = 1;
    TrackpadTwoFingerFromRightEdgeSwipeGesture = 3;
    USBMouseStopsTrackpad = 0;
    UserPreferences = 1;
    version = 5;
}


to set any of these keys type 

defaults write com.apple.driver.AppleBluetoothMultitouch.trackpad KeyFromAboveList -bool true