Why is my screen just black when I try to take a picture even when I hold it up to the light?

The "no images" thing is confusing me, because you should still be able to see photos you've taken. I wonder if something glitched.

Try doing a Reset (hold the Menu button for five seconds and follow the prompts).

Do you have a memory card reader? If so, put the mem card in it and hook up to the computer and try to see if your photos are still there. If you don't have one, it's worth a purchase; they run around 20 bucks and are available pretty much everywhere (Walmart, etc.)

As for the camera, there's a chance that your black screen is related to a bad CCD sensor. I don't know how that could affect your already-taken photos, but it's a possibility to explore if the Reset doesn't work. This camera was part of a recall on bad CCDs awhile back, and if that's the problem you will likely be able to get it fixed for free. Here is the link, which includes info on how to contact Canon:
http://imaging-resource.com/badccds.html