I just got a new computer with Vista, and I tried to download powertab. I downloaded it, and tried to open up a tab off of this site, and it a screen came up saying that windows didn't know what program made the file, but I already downloaded the program.
All of it is new you n00b.

Well, "select program from list" and browse to PowerTab, simple as.
Axe FX 2
Matrix GT1000FX
Mesa 4x12
Behringer FCB1010
im sure itll be fine, once they get the bugs sorted out