Ha Ha Ha Ha Ha.....
Not to laugh at the situation, but I never thought that my training as an Arachnologist would come in handy in this Forum.
I would say that nothting really serious will happen to your DVD Drive....the lense may get a bit dirty from trailing silk (most spiders trail a line of silk behind them, for various reasons, but mostly to save themselves from falls (sort of like a climbers belay line). If it left the system or not really depends on what type of spider it was. A cursorial hunter would wonder around looking for prey and would not saty in one place. A web spinning spider will look for a place to set up "shop" which for many means some type of dark place where they can spin a web (for most of the types found in your home). A light near the drive would only attract one type of spider found inside the home (jumping spider) but the heat given off from that would repel even them.
More than likely turning your computer on killed the spider since many are suseptible to dessication and we all know how hot and dry computers are.
I wouldn't worry about this........if you are, just stick in a cleaning disk ensure that your lense isn't gunked up.
Oh, and I won't pass along all the "fry it" comments to the very large spider sitting in a container in my computer room....or the scorpion for that matter either
