The pen pressure isn’t working. The pen is working on the screen for as far as I know but I don’t know how to fix it.  Anyone care to help?

Program I use: Paint Tool Sai

Windows 7/8

Type: Cintiq 13hd

Was I suppose to uninstall my old tablet’s junk? (Wacom intuos pro 5 (touch)

Did you install the cintiq drivers? I didn’t uninstall the intuos drivers when I got mine