Windows XP won't let you do that. But the command is format c
The problem is, as I said, Windows won't let you do that, So the only way I know of is to connect it to another computer or boot in LINUX (There are LINUX distro's that run off the CD drive) and reformat, Then reformat again.
The problem is some viruses will survive that, There is also a way to get at those, but it is more complex and beyond what I care to type.
NOTE: there is a program. I have an older version which does not work with Windows 10 (but does XP) called Acronis True Image. IT is a LINUX program that understands windows and windows formatting... I highly recommend it.
IT can do the job.. ANd what is more it can make a back up of your system once you have cleaned it.
Also a GOOD firewall and a GOOD anti-Virial will help.
Now: Question: What are the virus sysmptoms? I know my daughter handed me a computer once that had a black screen, Nothing on it, She could not get it to work (following an infection) took her husband 2 hours to get one file off it.
Took me less than 30 minutes to restore it to operation and burn a CD with all her photos on it... If that's the virus you have, the "Fix" is so easy you will face palm when I( give it to you.. But you need to run a good anti-virial after you get it back. I suggest Malware Bytes
NOTE: Staples can do that for you.. I do not know if it is still Free or not.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times