Problem with my photoshop/graphics tablet?

I use Photoshop CS 2007 and my tablet is a ‘HyperPen’ from Aiptek.

I’ve had the device for a long time and it’s worked perfectly with Photoshop ever since I bought it. (I use it for drawing). But suddenly, there seems to be a problem with it? Either it, or Photoshop.

The pen pressure just isn’t working anymore! The pen itself works in general because it does ‘click’ things and it does still draw – but the pen pressure brushes that are supposed to appear in Photoshop automatically are not there, even though I haven’t changed any of the settings. The lines are solid and there is none of the usual graduation (i.e. you press lightly and the line is small, you press hard and the line is large)
This makes Photoshop practically unusable for me, for what I would usually use it for, and I’d really like to get it fixed.

I hope I was specific enough – if there aren’t enough details just ask and I’ll add any extra information I can.