Kuchiyo, Can it be assumed that you have the floppies for DOS and are creating a new DOS 6.xx virtual disk?
If so then you need to format the new virtual disk with a dos formated floppy.
I would not worry about formatting your regular C drive as it won't let you do that, you need to run fdisk (which it sounds like you did) and then format the new vpc C drive using the /s option so that it is bootable.
as long as you are running in a Virtual Machine window, it won't let you format the main C drive.
Rich
My Computer
Computer type
Laptop
Computer Manufacturer/Model Number
Toshiba Laptop Qosimo X870
OS
Windows 7 Pro x64 SP1
CPU
Intel Core I7
Motherboard
Toshiba Qosmio
Memory
16 Gigs
Graphics Card(s)
NVIDIA GeForce GTX 670M
Monitor(s) Displays
17.7" laptop
Screen Resolution
1600 x 900
Hard Drives
256 Gig SanDisk SSD for C
256 Gig Intel SSD for D
Internet Speed
50/25 FIOS
Antivirus
Vipre (all you can eat for 10 machines)
Browser
IE and FF
Other Info
I have dos 6.22, wfwg 3.11, win98, 2000 and xp VHD's available for testing. MS's Virtual PC works great.