So, I foolishly bought a TI-89 Titanium on Ebay that was known to be in a locked up state. I've fixed locked up things before and figured I could here, too. Bad move. A thread here indicated that the hot car trick might fix it. I thought it had, but basically I think that was just due to removing all batteries for a sufficient amount of time. As far as I can tell, basically here's what it does: You remove one of the AAA batteries and the backup and let it sit for a while (maybe 5 minutes or so). Power it on and it works normally for a few seconds to a few minutes. Then it locks up completely. No button input works. Remove all batteries for a little while and it works again. If I insert a battery while holding down the (-) and ) keys plus ON, it'll go to the "Installation in progress. Please do not interrupt" screen. But then it comes up immediately locked up again on the main screen. If I insert a battery while holding down APPS and ON, it goes to the "Waiting to receive" screen, but is locked up. It isn't recognized by my computer or anything with a working USB cable. I DID, however, get to upgrade the software one time while it was in its temporarily working stage, so it's on the latest build (3.10). I just tried starting it up and immediately clearing the flash. No good. Locked up after getting back to the main screen. Did the same with the other ram later. Same result. Any other bright ideas? I'm kind of at a loss. I have no idea what would cause this sort of issue other than guessing it's a hardware issue. I've already ordered another one, but it'd be nice to not have this one be a total loss.