Clean Install Win98

[Anne Ugazio]

I am to attempting to clean the HD of an old laptop prior to donating it.
I have the Win98 cd that came with the computer when it was new.
I have accessed the BIOS, changed it to boot from the cd
When I type
D:\win98>FORMAT C: enter
I get
Invalid Drive Specification
rather than the directions to proceed with the formatting. What haven't I got right?

 

[DelJo63]

The CD will be the C: drive -- you need to look a what drive letters are active.

 

[Anne Ugazio]

The CD will be the C: drive -- you need to look a what drive letters are active.

The C: drive wasn't recognised. InstructionCD ROM drive which was D:
The instructions are from the Techspot website.
Here's a screenshot of the instructions.
At a bit of a loss as to how to proceed.