Bold 9900 (T-Mobile) has sticky 'A'

So, in deference to the Canadians on this forum, I know it's 'eh', not 'A'...but here's my problem.

Quite a while ago, I noticed shortly after T-Mobile's OS upgrade (to 7.1.0.284 (998)) that, on occasion, the 'a' key won't work after having been typing something in one or another application...BBM, Facebook, SMS, whatever. I don't think it's a hardware issue, as I can backspace/delete, at which point the 'a' works, but when I advance to the same point I was before, the 'a' doesn't work anymore. I can, often, just switch applications, and then return to the afflicted process...at which point the 'a' works again. Of some note is that when this occurs, the menu, touchpad, back, call and drop keys (basically all the main keys above the keyboard) also don't work (which makes switching applications difficult, of course). This also happens randomly when I also can't answer a call, or hang up, and I have to think all of this is related. But no other keyboard key is affected.

Having looked through old threads, I suspect my situation is unique. My Bold is almost two years old, having bought it on its first day of release (31 Aug 11), and it's otherwise performed flawlessly (as opposed to my 9700, which I'd been on my third one by the time I upgraded to the 9900). I really don't want to go back to the previous version (although for the sake of diagnostics, I may be obliged to, so no hard feelings if this is the consensus) but I'd really not want to give up WiFi calling, which comes in handy in those areas where T-Mobile coverage is spotty.

Any ideas?

Wow! Has it been since March (and before) that I lived with this problem? Well, the short story is that, despite how it presented, it was a hardware problem. I did a reset/debrick, to satisfy the CSR, only to find that my freshly loaded device, devoid of any other software, still had the same problem. It had by then actually spread to the touchpad, where any exposure to light would result in rapid, random movement of the cursor. I had thought that the new O/S (Bundle 2508) might have made it worse, even, just as the previous problem seemed related to the installation of Bundle 998.

A new phone solved the issue....but in the process of refreshing the device, I lost some of the applications downloaded from AppWorld that are no longer there (like Word Mole, or Crystal Spheres or whatever it's called). Not that it's a catastrophe, but does anyone have any suggestions on how I might re-install these, seeing as there appears to be a copy set aside under /BlackBerry/app_world/downloads/[mypin]/[application_name] on the media card.