okkkkk so I was having some problems with this program, and here are two fixes I found.
They work and now I'm happy.
First: Touch sensitivity
I have a Windows 7 comp and a wacom tablet.
So, first open the "Start" menu.
Search for "tablet preference"
A link labeled "Wacom Tablet Preference File Utility" should pop up.
Then, Click "Remove" All Users Preferences.
This fixed touch sensitivity....
On top of that, it wouldn't work at all -______________- it didn't even show up! when I clicked, nothing happened!
So here's what to do....
go to the folder in which sai is located. it could be "PaintTool SAI EnglishPack" or something like that.
A Configuration Settings file should pop up labeled "misc"
You should have the following: