oh okay yours is a little different i always forget bamboos are kinda funky-- OK BASICALLY if you click "advanced" there there
might be a thing in the newer wacom drivers that says this:
[IMG CLICK] you want that yellow bit checked if its there. I'm not sure if it is or isnt, it might be on the higher end tablets rather than the lower end bamboo drivers.
if that is not the case, and you HAVE NOT reformatted your computer recently (if the tablet was previously installed on this one) it might be a case of older drivers being stuck, you may have to reformat your machine or find a way to clean out the old drivers. Theres a couple explainations on google with that kinda thing if you need to do it.
its sort of hard to say what causes this sort of thing, drivers are really odd ESPECIALLY tablet drivers on windows 8, I've even had the company confirm a lot of people have problems with that OS and their tablets. sorry if this isnt too helpful it can be such a broad variety of issues and solutions these days.