I've been using Liquify for years without graphics processor turned on. What happens when you try to use Liquify with it turned off? Do you get an error message of some sort?
Perfect! Begin by adding a Channel Mixer layer, checking the "Monochrome" box, then entering 0, 0, +100, 0 for the four values.
Then post in the Levels Class for me so we can discuss it from there.