I have used the Win98SE fdisk to remove the XP NTFS partition without any drama.
What does he mean by a virtual C: drive, a RAMDisk ? That might explain it <G> !
The error massage seems to imply that he's only tried to reformat the partition using Win98SE's format command which won't work with the NTFS partition.
Before you go any further, you might want to make sure that your colleague is aware that all data on that drive will be deleted if you proceed any further.
Perhaps you could help provide your colleague with fdisk assistance.
You need to verify what partition or partitions are present and delete them all.
Next set up your primary partition - if the colleague is not fussed about having separate logical partitions then dedicate all the disk space to the primary partition. You should also check that it has been set to be the active partition - this is done by default but it's worth checking.
Once this is done, remove the boot disk and restart the machine with the Win98SE cd in the CD drive and make sure that the PC boots from the CD (If not, leave the boot floppy in the drive and follow the prompts).
Win98SE will automatically format the hard-drive before installing the OS.
If there is a second HDD detected with an operating system present, Windows setup will baulk, recommending you go no further.
If this happens, select the continue text - just make sure that when it comes time to determine the install location that it is set to install to C:\WINDOWS and no other path.
If any of this fdisking makes you or your colleague nervous, get yourself a well-known friendly neighbourhood PC-nerd to help you out <G> !
Regards,
zaphod38