the tab is closed too (on underside of dick) what switch do you mean? is it on the comp or the disk?
On the floppy disk, the little tab should be set so that the hole is closed. That is Write-Enabled.
On the Amiga, you can get a small flashlight and look in the floppy drive. On the left-hand edge, you should see a little bar (1/16th" thick, or so) that is sticking slightly above the plastic casing. This is the visible portion of the switch for write enable/protect on your floppy drive. As Doobrey said, there may be dust or gunk on this switch. Try a little blast from a compressed air container on it to clean it off.
If neither of these work, you may have a batch of defective disks, a defective floppy drive, or a damaged floppy drive cable, or in the worst case, a damaged A1200 motherboard.
The diskettes are the easiest to check. The A1200 likes 2S/DD (Double-sided double density) 3.5" disks, not HD (High Density) 3.5". There should still be a few places that sell semi-new 2S/DD diskettes. Though they are getting fairly rare. If your disks have a HD logo (or CH, if you're looking at it upside down!) on them, the A1200 MAY still be able to use them in DD mode, but may sometimes encounter read or verify errors.
