I don't think anyone wants to portray you as an idiot really. We're just having a little fun with you, it's all good hearted really.
Formating anything without knowledge of the operating system, when you are asked to perform maintenance duties, is not exactly the best move. You did made a couple of very non-geek-worthy assumptions:
Thinking 120mb would mean 1.2mb. I don't know about you, but every computer I've used tends to give me the right size for its disks, give or take a few k's.
Since you brand yourself a windows geek, you should be used to disk labels. On windows, I call my C "System", D is "Programs" and E is "Data". Trying "Format System:" won't return anything, but "Format C:" might very well format my C drive

Thinking there are no such things as 880k disks is also not very geeky as Macs have been using similar sized disks back in the days.
1.2M floppies also exist, they are high density 5.25 disks. So they are not a little off from 1.44 disks.
Also, you most likely didn't read correctly when you say that DH0 was 880k. It is unlikely that the boot partition would be this small. Most likely it was DF0. Understandably if you don't know anything about the amiga, you might not have seen the 1 letter difference.
Ok enough about pointing errors out.. here's some tricks and a little amiga crash course:
1- What you call a Desktop is the Workbench on the Amiga.
2- Not all files will be displayed on the Workbench. So opening a drawer (folder, directory...whatever) and not seeing anything does NOT mean its empty. The icon information of a file is stored in the .info with the same name.
3- Right-Amiga + E is the equivalent of Start->Run. You can used R-A + E and then type CLI to open a command line shell. It works as you would expect with commands like DIR, CD, MD and the such.
4- The amiga does not work with a registry to know where it's system files are but rather with a set of pre-defined drawers on the system/boot drive. The C drawer for example contains all the commands that you can invoke from pretty much anywhere (usually a command shell, obviously). The LIBS drawer contains libraries and so forth.
5- 99% of the time, the system drive is for the system only. Very few users will install programs in there and I doubt that yours differ. Programs and data are generally kept elsewhere (dh1, dh2 and so on)
Not knowing exactly where the programs and data were kept on the system, it is hard to tell you what exactly you've deleted. One thing is certain: a half-formated drive is no good. Backup what you can from the half dead DH2, and do a proper format before putting all the data back.
With some luck, the guy who setup the computer did a clean job and DH0 is the system, DH1 is the program disk, and DH2 was where the data was being kept. If that's the case that would mean only the data was lost. Format the drive properly, find the weekly backups and copy them back onto DH2. Apologize to the people who hired you for the lost data, and don't expect any money from them.
With a little less luck: DH0 is the system disk, DH1 is the programs, and DH2 is both the data disk and the backup disk. In that case, you're pretty much screwed. As I said, an half-formated disk is no good. You might recover some data, but you are most likely to get corrupted data which is going to cause as much problems as not having any data. That will require you to run DiskSalv and other similar applications. I would advise you NOT to do this as it is beyong your abilities. I'm not saying you're an idiot now.. I'm merely saying that if you managed to screw up on formating a floppy, chances are you'll do more damage to the system with "low-level" system tools on an operating system you're not familiar with. Get someone who is familiar with the Amiga and get him/her/it to work it out.
So sit down with the person that is normally using this computer and ask him where he used to click to perform certain tasks. Try to figure out where the data was save first and foremost. Data is the only thing you're after. Programs can be recuperated from the 2nd Amiga, Aminet, or anyone here...we'll help you out on that if we can. If the data was on the formated disk, it's gone, forget about it. Copy what you can from the dead drive, and store it somewhere safe in case that is all you can salvage, then format the drive properly.
Was the backup automatic or was it done manually? If it was done manually, ask the person where he made the backup and hope he doesn't point you to the formated drive. If you can access the full back up, you've only lost a week of data and just getting the system back on track will most likely satisfy your 'customers'. If it was done automagically, what software was used? Run it and check it's configuration to know where the backup was made and see if it's still allright.
If the backup and the data are gone, they are gone. Change name, sex and underwear and move to another city
