when you run fdisk, you need to make the C: drive on your iopener disk active...i.e. in the menus, set active partition.
And you need to make sure you did a "sys c:" (or whatever drive it is) after you formatted it, to put the dos boot stuff on it.
BTW you cannot make any other drive partition active if you have a windows or other boot drive installed at the same time.
In other words,
In you main machine that you used to copy the data from...disconnect the HD (power anyway, or both power and data) that contains the C: drive. Either plug your 2.5" drive onto that header, or another one...doesn't matter as long as the primary drive is off.
Just did this...forgot about setting active partition, pulled hair out, then remembered.
You will have to boot from a win98 boot disk to do this and run fdisk.