Worst? I dunno, I've had so many... I'll start with a few.

Scenario 1- '97 (I think...)- My family got our first comp. Twas an IBM Aptiva(555 maybe? It's in my sis' room now). Now I used to be on that thing all the time, and I once learned... tada! how to download! I was restricted to aol, but i downloaded all the games I could from there, well over 40 games, and played them, and the ones that came with the comp (tons, i remember it came with mechassault 2, and Lotus 1-2-3... ok so maybe Lotus wasn't a game, but why not install anyway? :P). After I had downloaded all this in my 56k download-binge, our computer mysteriously started losing mouse function, with windows not detecting it (this later became a historic beginning to the other ones I owned). My mother called IBM, having no clue what was going on, and it was all because of Hard drive space XD. She, being less informed than I at the time, doesn't trust my advice and lets someone 'take a look at it', who installs Win98 and a an ATI video card, makes the speakers built in the monitor not work, etc and charges her a considerable amount on top of that. It is now in my sister's room, devoid of use most often.

Scenario 2- Later my mother bought a gateway. i could download more, but not much out of courtesy. Now here's where I did something that wasn't bad at all, unless you have an mother like that: I changed the properties of the recycle bin so that deleted files would skip it entirely. What is wrong with that you ask? Nothing, except maybe that my mom (the genius she is, god bless her XD) stored legal documents in the recycle bin thinking no one would look there...brilliant.

Scenario 3- The first laptop I ever got. It was used, I checked all the info I could that it was a good buy. An older IBM Thinkpad (something 775), priced at $250. Now if you haven't noticed, I have a tendancy to delete very little, and this laptop had a 995 meg drive- bad combination. I load alot of my cd's and such onto this bad boy so i no longer only had them on cdrom, but slowly keys stop working (the 2-3 days after I bought it). I find a hardware solution, considering these were the ones with quick removable keyboard: press down a small wire in the back of it and the keys worked fine. So I use some 'ingenuity' and stick a small folded piece of paper under the keyboard so it'd hold down that wire for me. The next time I reboot, very few of the keys work. Whats the major problem in that? The comp had a bios password when I got it., and none of the number keys i needed to ener that pass were there. What is my solution? I remove the CMOS battery and it works a bit. After awhile, though, for some unknown reason, it just died starting up one day. Now all I had was a high tech night-light, that hung right after shoeing the wallpaper background I had and never fully loaded windows or any of that. I was forced to trash it.

Those are only 3, and I've been through alot more, but thats a bit of history as is. I haven't lost the lessons of all those mistakes to this day, so I'm still optimistic. I have tons more horor stories but those are the historic selections.