I own a Cannon A700 and inadvertently put my software on auto start. No matter what I push on my camera I am basically locked out with just the Cannon icon with blue background showing. The lens also reopens every time I shut off the camera. Could sure use some help getting out of this. Guess I didn't get the basics of using the script.
Hard to tell from your description what you were doing or if it even relates to CHDK.
But here are a couple of things to try :
1) Pull the battery and SD card out for a few minutes.
2) Put the battery back in but leave the SD card out and restart the camera. What happens ?
3) Reformat you SD card on your PC so that its blank. Put it into the camera and restart the camera What happens ?