>there should be an item in the Media menu that says "ASIO (via portaudio)" that should be checked >in order to use the ASIO drivers.
Yep, there should be. I use ASIO via portaudio in Windows XP with PD. Maybe your ASIO is not well configured.

>I seem to detect a bit of Linux snobbery in that comment. I'm a big fan of open-source software, and if >you can suggest an open-source DAW for Windows that has all of the features of Cubase (by which I >do mean "all," not "some"), I'll be overjoyed to switch to it as my primary platform! But if I have to do >without important features ... not gonna switch.
It wasn't meant to be snobbery, just showing possibility and a comparison with my XP and my Ubuntu on the same machine - but definitely I don't want to generate a "windows vs. linux" thread :D
As for open DAWs, Ardour is very good. I've used Cubase 5 because in one of my musical projects one of the members uses it to record, and it is very very good - a lot of interesting improvements from the previous versions (I recall using Cubase 3 some years ago). I don't have the time to compare all the features of Cubase v.s Ardour but I know some that Ardour is leading is OSC support - which is a really nice feat (irecall reading this [1])

Best regards and keep posting the results, maybe we can figure out what the issue is,
Pedro Lopes

[1] http://createdigitalmusic.com/2010/04/07/want-a-daw-that-supports-osc-try-ardour-free/

--
Pedro Lopes
contacto: jazz@radiozero.pt
website: http://web.ist.utl.pt/Pedro.Lopes