Project 1999 - Memory access issue under Windows 10

I just got a new Windows 10 tablet.

Being perverse, one of the first things I did was to copy my EQ installation from my desktop to the tablet. (after hooking up a bluetooth keyboard and mouse).

I tried to run it, but it kept crashing, with a message about trying to access memory that wasn't there (the tablet has 8gb).

I edited the EQClient.ini file, setting the resolution, both full screen and windowed, to match the tablet's 1280 x 800 display.

Now I would get as far as logging into the game, but as it was loading, it crashed again.

Eventually a friend suggested I try logging in on his account, instead (yea, I know we're probably not supposed to do that, but this was just for testing purposes, not to actually play).

Boom. No problem, all the way in. Logged onto his char, walked around, smooth, even when around people fighting and casting spells.

Figuring that somehow in the process I'd fixed it, I tried to log into my account again... boom, crash.

Logged in on my desktop (on my account) instead... no problems.

I'm guessing there's some configuration specific to my account (rather than my machine) somewhere that's messed up, probably having to do with the screen resolution, but I haven't been able to find it.

Anyone have any clues as to what might be causing this?