OK I admit it, I thought it was something I was doing incorrectly... or something I was doing caused by being in and out of various versions of various software or something, but I've got a collection of .chm files that won't open. I found that tapping on the monitor didn't help anymore than yelling did either, except in some cases, yelling made me wipe off the monitor and that got rid of all that dust :)
Point being, there's a reason why I can't open them, and it has nothing to do with ME.. woohoo!
I came across this blog post from Rob Caron this morning after ratting around in the MbUnit documentation:
Viewing Downloaded CHM Files
or then again, since this blog post is from June of 2006, maybe I'm the last one to have heard about this :)