Pen strokes going mad- (HELP NEEDED)

[star_boy]

> Okay so. Long story short. <

> I've had my Wacom tablet for around 10 days now, and everything was going fine. I was drawing a character to submit from DeviantArt when I had to restart my computer because it crashed <

> When I got back to PaintTool SAI, my lines were straight, like I had the shift key pressed down when I didn't. It only drew smooth lines when I constantly had my pen pressed down, which isn't helpful at all <

> Can anyone help me with this? <