OK, thank you for answering!

But I decided to first low-format my old HDD by using Magic_Boot_Disk_ISO_v2.0.iso and I need some help. So, here is what I'd like to do:
I have a WD2000 (200GB) SATA HDD and it's possible that it contains viruses/malware, possibly even in the MBR/boot sector. I will do it with on an older PC of mine which could also be infected, that's why I'd like to use Magic Boot Disk from hddguru.com site which includes MHDD tool in a zip file to do it in a clean (DOS) enviroment.
So tell me how to do that properly (so that EVERYTHING will be low-formatted on that WD2000 HDD) and so that when I stick back the old drive the PC will work as before and I'll have a formatted spare drive which I can use or sell.
Please write me what to do first. I guess I have to burn the Magic_Boot_Disk_ISO_v2.0.iso to a CD-ROM, uninstall the present HDD and install the WD2000 in it's place and then boot the PC from the Magic Boot Disk CD-ROM. But what then? Do I first use FDISK or do I first pkunzip MHDD (where?) and how do I use it? In short, how do I low-level format entire disk, including MBR/boot sector.
Additional questions: should I first check the HDD for errors (or check it for errors later or not at all), should I fill the disk with zeros (how?) and should I low-format it again later in Windows (using HDD Low Level Format Tool)?
Thank you A LOT for your help!
