Constant Hang during "Import Video"

No matter what I try, the Vista "Import Video" window hangs forever.

Here's what happens:

I plug in my capture device into the firewire port of my Dell laptop, then
AutoPlay pops up and says:

"Digital Video Device"

Device Options

Import Video <<-- (this is what I choose)

Capture video (If I choose this, it doesn't work)

Start Encoding"

Next window comes up: "Import Video

Name: xxx

Import to: (folder)

Format Windows Media Video (single file)
WMV (about 2 GB per hour)"

I press Next, then the new window says: "Import Video

Import the entire videotape to my computer

Import the entire videotape and then burn it to a DVD

Only import parts of the videotape to my computer" <<-- This is what I choose

Then I press "Next", and then it hangs forever
(the window title bar shows: "Import Video (not responding))

I've tried everything, including registry repair and running Iolo's System
Mechanic 7, but it still hangs every time. One key fact, though, is that
this worked PERFECTLY two days ago!

I'm a knowlegeable user, so please bear that in mind in your replies.

Thank you for your help!