I do that every time it comes up, and it keeps coming up. Wanna swap computers? You seem to have found the magic button that REALLY disables it
I didn't actually bother to check it when I gave instructions previously, but I just did now, so I know they work.
In the Accessibility options click on Settings next to the 3 options on the first page and disable the shortcut key for each. That's what the real problem is. I just tested this on my home (gaming) PC -- hitting shift key several times quickly brought up the damned dialog. I clicked on settings or options or whatever the hell the 3rd button was, then went into Settings on each of the "features", turned off the short cut keys, and clicked OK on the main dialog. Hitting shift rapidly no longer brings up the dialog box from hell.
Oh, and Kevlar said this correctly first, but I thought I'd reply as well and steal all the glory and fame.