You have made this much, much too hard and complex. There is a simple, almost trivial solution to this that is easily extensible. I have currently Win98SE on a FAT32, WinNT WS on NTFS, WinNT Server on NTFS, and Win2000 AS on NTFS all on one machine with the capability to select any one upon bootup and without any recourse to third party software. 1. Create a small FAT16 partition (50 MB enough, I use 200 MB to allow for ill-behaved installation programs to create temp files). This is C:\. 2. Install Win98 (or Win95 or any other DOS-based OS) on a second partition that is sized and formatted to your liking. In my case I have a 1 GB FAT32 partition on my second hard drive for Win98SE. It can be on the same disk as C:\ and can be a logical drive on an extended partition. 3. Install WinNT or Win2000 (any flavor) on a third partition that is sized and formatted to your liking. In my case, I use 2 GB NTFS partitions for each. Some are primary and some are logical in an extended partition. Key factors are installing the non-NT/2000 OS first and keeping each set of system files on its own partition (also you generally have to install applications on each OS individually as sharing an app between OSs in this setup is very, very tricky if it is possible at all [application dependent]). The only problem I have run into so far is that when booting into Win2000 AS, all the WinNT 4.0 NTFS partitions cause minor errors to occur since they have not been reformatted to include all Win2000 capabilities. They still work, just not with all the bells and whistles Win2000 brings to the table.