So, I guess I might say that I own a TI-Nspire CX CAS, and that is partially true. However, the one I use is my brother's, because mine broke...
I was wondering if I could take it apart, but I am not able to without buying outrageous types of screwdrivers...
Ok, now to the description of the problem. I originally thought that these problems were caused by Ndless, but now I realize it is probably a hardware issue.
So, one day, I discovered that the screen looked corrupted on my TI-Nspire. I kind of freaked out (I think? I don't remember...) Anyways, once I reset it, it was fine, until it corrupted again. Sometimes it would boot with the old non-color TI-Nspire boot screen, which I didn't think was possible for a CX model. Eventually I had to press on+reset at the same time to get it to boot. Reinstalling the OS and formatting the device did not work. Nearing the end of its life, I had to actually twist the calculator to get it to boot. Yes, I had to physically twist the calculator, which was probably the best indication that it was a hardware problem. Now, it won't boot at all...
It definitely sounds like a false contact on the board if you had to twist it so it works. You might want to open it, any hardware hackers here?
Also I think I should add that it's warranty is probably over or voided by now, depending on if installing Ndless voids it (I assume it does)
Nope, installing Ndless is clearly not known to void the warranty :)
And yes, it's hard to conceive that such misbehaviour can be produced purely by software.