recently my floppy drive became unusable. i can read from it fine, butt iff i write anything to it the file becomes scrambled. i thought it was a bad disk but it's not. even reformatting is no help. i thought it was a bad drive, changed it. i've put in a new cable. i even disabled the on board floppy controller and installed a floppy controller card still no good. any clues as to what is wrong? michael galante