Mac Mini :: Crashes - No Double Clicking / Highlighting And Command Key Failure

My perfectly wonderful Mini has started doing the following, in this order:

First, I could no longer double click on a word but the right button functions still worked (and yes, I did try another mouse and had the same problem, then I switched the mouse preference to double click with the right button, but had the same problem). This started two evenings ago.

Second, the next morning, I suddenly couldn't drag the cursor across a word, or a sentence, etc. Now it was really getting annoying, because in my work I paste and copy a lot, and this caused me much, much extra work, so it's not a minor gripe.

Then, by that afternoon, I had a complete system crash. The whole screen froze. I tried turning off my Mini with the power button (which I hated because I know you're not supposed to), but the screen remained frozen.

At that point, done disk repair thing from my original instal DVD. Well, it unfroze the screen, but did not fix the mouse/cursor problem. Clear the PRam. That still didn't work. The next morning (today), it crashed almost immediately. Again, totally frozen. This time, I reinstalled the entire system from the instal disk. No luck.

I came across an app I'd bought the last time I'd had bad Mini problems (and had forgotten), called Disk Warrior, so I tried that. Well, it did find three unfixable, corrupt .plist files that it said could cause system disruption. I thought I'd found the problems. So I deleted all of them AND their apps, downloaded fresh copies of the apps, and restarted. Still same problems.

So, I ran Disk Warrior again, and it reported those same three corrupt plist files. Then I realized it was reporting the ones in the trash, so I emptied the trash, ran Disk Warrior again, and it said NO problems. Restarted and tried to highlight some text, and it worked! But it still wouldn't double click.

Info:
Mac mini (Mid 2010), Mac OS X (10.6.8), Mac lover since the SE