Are modern floppy disk drives compatible with 720kb DD floppy disks? I tried using 720kb DD floppy disks on my PC and computers at the University and I wasn't successful. It kept saying that the disks are not formatted properly. I know for a fact that the disks are formatted properly and work.

Is Windows XP compatible with DD disks?

Well, all I can say is that all my floppies are completely "dead" by now... that's mostly because they are very old.
I keep half a dozen of them just by sentimental reasons, and I don't even try them in my floppy drive because I'm almost sure they will not work.

Anyway, I don't use floppies for more than 5 years now - and with today's "pen drives" having capacities of around 1GB it makes no sense to use floppies.

Now about your question: you say it's a 720kb floppy, from which I deduce it's one of the first and so, a very old one. For most certainly its data is corrupted - probably even its partition table is damaged, that's why it says it is not formatted. I don't want to disappoint you, but I would bet it's permanently damaged, so don't expect to get anything from there.

I guess they are formatted for Amiga as DDs were mostly used for Amiga. As much as I can remember they had no difference, just a little hole on the upper corner. We were breaking the upper corners of DDs and formatting DDs as HDs, I was so mean :whistling:

There should be no problem if you re-format them. Even a 5.25'' floppy should work with XP as much as I know.

I'm quite sure that I used a DD floppy on a WinXP machine some time ago and I think that there should be no differences in "formattation" respect the HD floppy... Anyway, probably Shrek is right saying that that kind of floppy could be all corrupted now...

Of course there is no difference but if you format it for Amiga, you won't be able to use it for PC. Just like PlayStation Discs not running on PC. In order to use an Amiga disc with PC you need to re-format it. I just tried to say that there are two possibilities, it's an Amiga disc or it's corrupted while the latter is more likely to happen.

Windows xp cannot format 720 kb floppys.