About thirty minutes ago I stepped away from my PC and came back to find the hard drive writing like crazy, the no CD DRM box on the screen and my friggin mouse lost calibration.

I hard rebooted and now my computer is working the best that it has ever worked.

Is this kind of like coughing up plaque that was clogging an artery?

My first instinct says background defragging, explains the hard drive thrashing & improved performance

"the no CD DRM box on the screen" Whats this?

A ghost is messing around with your PC. Call an exorcist.

Yesterday when I was messing around with Borderlands, I took its CD out of the drive before closing the menu screen and I got the "No CD in Drive" prompt which I couldn't even cancel out of until I stuck Borderlands back in and hit cancel.

The only other way to get that prompt to close is via task manager.

Anywho, I kinda thought that lil' mishap yanked a wire that came back to haunt me right now but not sure why the mouse would lose calibration and keep slipping down the screen or send the hard drive spinning.

a wild guess:

you are using Windows Vista or Windows 7?
If so, when the system is idle, it will run several tasks like defragmentation, virus checking and indexing the files (for a faster access).

Naw, XP 3rd Service Pack but I do have bought version of Advanced System Care Pro that pops up randomly for a cleaning every now and then.

Sure, either that or the advent of the long expected "singularity". Computers developping self-awareness, and starting an evolution of their own.