So, worst computer disaster(s)?
One would certainly be the ruined laptop due to water dripping from the ceiling back in '13, but the silver lining (which understates it, this really was a damned miracle) was that the hard drive wasn't in danger and for thirty bucks it was removed and installed in one of those little cases with a USB cable so I was able to get every damned file off of it. I was so grateful for that, that even though I've backed my stuff up prodigiously since then, I still keep that little hard drive in my desk drawer out of pure gratitude and perhaps a little bit of superstition, four years after the fact. But I had to replace that computer way before its time, so I still count those few days of uncertainty, and then that expense, as a computer disaster.
Prior to that, I'm mostly wistful about a handful of Word files in the late 1990s that, for some reason, I decided to password. Somehow or other, I ended up utterly forgetting the goddamned password -- which is totally unlike me, but I also suspected that something weird happened to those files through another computer replacement or the moving of a bunch of stuff or...who knows. Looking back, there was one file in particular that contained my description of a series of events that, to this day, I'd still like to have back, even though it's inconsequential in the scheme of things. It's bugged me whenever I stop to think about it, and that was eighteen years ago.