Thats okay for asio4all that you don't see any input or output device. Do you have activated the first two stereo- and monochannels in the input and output channel configuration ?
Open the hardware setup and switch asio4all to the standard configuration and change the buffer size in ableton to 512 ...
just an idea. I am also running Vista with Asio 4 All on Ableton. I have the problem that I have to switch between headphones and speakers in my windows audio settings. So I am not hearing anything when I use headphones when I am not switching to them and the other way around with my speakers ...