Which computer are you using now? What made you decide that the Dell needs a COMPLETE overhaul? The 98 computer was using FAT (file allocation table) 32 for the hard drive. Windows XP uses NTFS for the hard drive. Are you switching hard drives? or maybe you weren't given all the right info.
Spybot-Search and Destroy is a very good program for cleaning a computer, it's free (not even registration), just put the name in the search bar and press "enter". Microsoft Vista is due out early next year, if you will be uploading anything to office networks, consider if there might be a compatibility problem with their O/S or word processor.


http://www.microsoft.com/windows98/default.asp
http://www.microsoft.com/windowsvista/getready/capable.mspx
http://www.microsoft.com/windows/ie/default.mspx
http://www.sysinternals.com/blog/2005/10/sony-rootkits-and-digital-rights.html

FWIW, wanting to wipe a hard drive clean so as to do a fresh & clean full install of Windows OS is without a doubt one of the oldest, most tried and trusted methods for clearning up PC problems, regardless of the true source of the problems (be it the Windows OS itself, virus/hack/worm, or otherwise). You sound like maybe you've been this route before, so you may already know this, but for the benefit of novices, this puts you on the hair edge of the Windows-pc-computing experience......... how about some oohs and aws or spooky theme music?

I am hesitant to provide the info that may be mistaken as the one-and-only step-by-step instructions for how to reformat a hard drive and install an OS from scratch. The biggest reason why is, while this general procedure is fairly well known (it should be, many, many people have travelled this particular road), it is not necessarily an exact science; translation - there are variables, and depending on how the variables line up from one pc & person to the next, the person and or the pc may end up falling off the hairy edge, quite possible never to return again.

There are a few basic tools that, if one has them, will greatly improve the chances of successfully navigating these format & reinstall waters. Do you have a boot diskette for the version of OS that you want to reload from scracth? Does your system have a floppy drive with which to use such a boot diskette? Do you have the original Windows OS install CD (IE> Install CD, NOT Upgrade CD). Do you know how to program the basic instructions & drivers for telling your computer how to recognize that it has a CD Rom Drive installed? Does the system in question have a BIOS that supports an option that allows the PC to boot from a CD Rom Drive? If the answer to any of these is no, the hairy edge beckons even more for you.

One last note of advice, if you have a system that is infested with viruses, it's conceivable that even a re-format of the hard drive and re-install of the OS will NOT remove the problem. It depends, there are many possible variables involved, just thought I'd mention this as another CYA. For the same and similar reasons, it may be a self-defeating action to back up any of the data on such an infested pc prior to re-formating and re-installing the OS.

With all of the above having been said, the way to "wipe my computer down to all 000000's" as you say is with the command

format C: /s

The above information is plenty enough to make anyone dangerous, so to speak, with a computer. Be very careful with this information. Good luck and may the force be with you.

Okay, this is only my humble opinion. I strongly believe that a full format of a hard drive and fresh installation of Windows XP is a sure fire way to rid your computer of any viruses/trojans/worms/spyware that may have quietly bypassed your defenses and may be quietly lurking in your computer sucking up resources, causing unexplainable errors,etc., If you ignore this, eventually your computer may crash taking all your important data with it. So, if you are going to be forced to eventually do a full format, you may as well get it out of the way. In fact, I believe that one of the best ways to completely keep viruses/Trojans/Worms/Spyware out of your system, is to consider doing a full format and reinstallation of Windows XP every 3-6 months whether you need it or not. Think of it like doing liver maintenance Liver Flushing to rid your body of accumulated toxins/ parasites that may be making you ill. Remember, it is like a cat and mouse game between those who engineer anti-virus and anti-spyware programs and those that engineer and distribute viruses/trojans/worms/spyware. Sometimes, the virus and spyware distributors are ahead of the game and sometimes the anti-virus and anti-spyware distributors are ahead of the game. That is why you can never assume that you will always be 100% safe from these threats even if you run the latest protection software, especially if you are running WindowsXP instead of Linux or Macintosh. You may just happen to be the victim of a new undetected virus/worm/trojan that happened to be making its rounds, and the counter anti-virus definition/spyware may have been too late coming to save your computer from any damage that may have been done. Grant it, you may be lucky and this may never happen.

Now, the tricky part when it comes to formating hard disks is making sure that you have access to the latest hardware drivers that came with your computer before you undertake this task. This is really important, otherwise you will be hunting the net forever trying to find the latest drivers for your computer and your computer may not work properly. For instance, I have a Hewlitt Packard lap top that came with driver recovery disks. Now if I ever lost these, I would be up Sh*it creek without a paddle and some of my computer's hardware may not work properly(SM Bus Controller, etc.,)

Now for a step by step of how to reformat your hard disk and re-install windows XP, this is a good guide.
http://www.lifehacker.com/software/windows/geek-to-live-how-to-format-your-ha...

By the way, my advise to you is that if you have lots of Trojans/Viruses/Worms/Anti-Spyware you may want to reconsider not reinstalling your old programs that you saved from the infection to your newly formatted computer, otherwise you will risk reinfecting your computer. It is like someone who has a severe cockroach infestation in their home that has got into all the furniture. If they, sprayed down the whole house but kept the severly infested furniture in their home or took the infested furniture into a new home, they would create a high risk of infesting their new home.

Finally, set your computer to boot from your CD Rom and consider trying one of the live linux CDS that I mentioned in my other post. This way, you can do things at a leisurely pace and won't have to worry about rushing something that may take endless hours because you are unable to access the Internet.

Hope that Helps
Good Luck and Best Wishes.