Hi. Hardreset the device in the following way:
If your LG Optimus Q/Slider is frozen/forgot pin/password, pull the battery out and reinsert it then. Then press hold the Home button + Volume Down button + Power button until the device turns on and displays the Android Recovery Screen. Use the Volume down key to highlight "Wipe data/factoy reset" and select it with the menu button. Scroll with Volume down and highlight "Yes - delete all user data" and select it with the menu button. Select "Reboot now" and you should be done.