You can NOT call an MSN account with Gizmo. MSN is not using a standard SIP protocol for video nor audio (they're using their own proprietary protocol, ref: http://en.wikipedia.org/wiki/MSN_Messenger ). So you shouldn't even bother with that--you're stuck with using Microsoft to talk to Microsoft there.

Also, you're right--Skype for N800 has no video support. Skype being pathetic and showing me why I'm not particularly happy with Nokia's level of dedication to keep this platform relevant.

I don't know what to tell you, but I was able to successfully make a video call with Gizmo to my brother's Windows PC from my Nokia N800. I don't think I did anything special except to make sure the Windows version is the newest one with the video call support. It sounds like your friend should try going into Gizmo's preference menu and choose the AUDIO tab (on the left) and look to see what audio device Gizmo is set to use. Make sure it's set to using something appropriate (USB headset device, internal sound card with headset plugged in, etc.).

Come on back here and let us know if that didn't work, though. I can't imagine "no audio devices are available" can't be resolved.