Thanks for the tips. I did wonder if the laptop's heat would prevent, or at least delay, the dew problem. Better to ask a silly question than to find out the hard way that I should have done something.
For now, though, I have circumvented the problem by buying a 5 metre firewire extension, which means I can have the scope out on the patio and the laptop on the dining room table. It was much easier trying out the software and getting my head round using the camera in relative comfort, but it will only last as long as my target is in the east or south (perfect for Saturn right now).
Enjoying the camera though. I have captured a picture of Saturn, which although not up to the standard of some on this site, I am pretty chuffed with as it's my first one (my non astro-minded friends find it impressive at any rate

). It's a bit fuzzy, but it was rather turbulent that night (not helped by planes out of Stansted flying right under the target), plus I was more interested in learning how to actually capture an image and less worried about what it would actually look like. My only disappointment with the camera is the fact that there is no manual for the software - seems geared up to someone experienced already in digital imaging. I am just going by trial and error right now, trying to find out what all the gadgets are. I had never heard the word codec before, for example. Also not entirely sure I am using Registax properly, but whether that is me or a poor video to begin with I don't know.

Still, my imaging experience extends to all of 2 evenings so far, so I have a way to go yet.
Would post to the gallery but I don't have a website set up to put the images on yet.
Rachel