On Fri, 9 Apr 1999, Jason Willgruber wrote: With a few exceptions (and I doubt that the APC III would be one of the exceptions), the 720K 3.5" can simply be cabled to replace the 720K 5.25". The original design of it was intended to permit that. But that doesn't solve your need for a boot disk. In an earlier message, you mentioned that your current boot disk is "Stoned". If so, a bit of work with a sector editor might fix it. Try to resurrect the 2.11 boot disk that you have. MS-DOS 2.11 was the version that MICROS~1 provided for companies that needed/wanted to customize for special hardware, such as 720K drives. PC-DOS didn't support 720K until 3.20. Previously (MS-DOS 2.00), sometimes only MODE.COM, and sometimes FORMAT.COM, varied from one brand of machine to another. But in 2.11, IO.SYS might be significantly altered.