Preview No Longer Opening Images, PDFs, et cetera

Good evening,

A while ago I installed the trial version of the Adobe CS2 suite. Today, all the icons on my desktop (and elsewhere, but desktop was most apparent) associated to PDFs, images, etc, that would otherwise be opened in Preview changed from their traditional icon scaled-down image of the file contents to the Adobe icon.

I tried to open them in Preview with no joy. I then went into Get Info and tried to change the default program to open with. Preview was grayed out, so I had to select "All Programs" to choose it. Still no joy.

I trashed the Adobe suite (I am no longer using it) followed by a reboot with no effect on Preview.

Is there a way to fix this? I have no easy way of grabbing another Preview application off of another Mac and I'd rather not reinstall my OS, but I have the disk to do it with. I attempted a software update. Still no joy.


Specs:

Macbook Pro 15"
Mac OS 10.6.2
2.8GHz Intel Core 2 Duo
4GB DDR3

Preview version 5.0.1

.png, .gif, .jpg, .pdf, and other file extensions have been associated with Preview.


tl;dr:
Preview will no longer open the files it used to. No apparent reason for the error and no apparent fix.

So what you're saying is that Preview (the application) no longer exists on your Mac?

Preview exists, however from what I can tell it has no usable functionality. The program runs, but will not recognize images or pdfs.