I have a SanDisk ImageMate CF, and the other night I was installing a bunch of files onto my CF card. I went to access the drive a second time, and the computer froze. I went to restart my comuputer, and the damn thing wouldn't start. I took my CompactFlash reader and went to use it at another computer.
The same thing happened. That should have been a clue to me, but I tend to be dense sometimes.
Then, I went to my previous computer, and it started up fine. Tried the CF reader on it, and it hung up. I finally started to make the connection- along with the fact that the CFreader was making a high-pitched noise much like a lightbulb makes when its dimmed to just the right frequency.
I tried to open the thing for about an hour. Turns out I missed two screws under the device's rubber noskid feet.
[Edit- about here I was asking for help, but I found the probelm after some more inspection thus edited my post. ]
Anyway, I opened it up and immediately recognized the problem- two of the reader prongs had become bent as so to touch each other and go into the same slot on the CF card. Easily fixed with needle-nosed pliars.