In Dec. 2005 I built myself a brand new PC from scratch...got a brand new motherboard which just came out that year, got my 700W powersupply, super duper graphics card and a HUGE sharp looking case to put it all in.  But, I wasnt going to buy new Harddrives or DVD/CD ROM drives because I previously bought a Dell Insperion XBS back in 2000 and still had everything from this computer.  My windows XP disk was the same one that came with my Dell in 2000.  Everything installed on my new computer and life was great. 

Sometime earlier this year I managed to get a virus/trojan horse which totally screwed up my hard drive (40GB Western Digital IDE HD-from my 2000 Dell).  So my desktop has been down for a bunch of months (thank god for my apple laptop) and now i'm trying to put the pieces back together on my MONSTER desktop.

Now that I'm trying to reinstall windows XP, I'm getting the message that "windows setup can not detect any hard drives" when I get to a certain point during installation.  Why would i have this problem suddenly now using the same disk to install windows that I used when I first built my pc in Dec 2005?  I realize this disk is quite old, pre-service pack 1 even - but I didnt have this problem in 2005.   I searched google and found some others with similar problems, but didnt quite understand their solutions (most of the problems dealt with SATA HD's while mine are EIDE).  I also read this microsoft article:  http://support.microsoft.com/?id=314859

which relates to the problem.  Why would I need to install extra drivers (which arent on the xp disk) now when I didnt have to previously?   Could the virus/trojan screwed something up I dont know about?  I've checked my Bios, the Hard drives are being detected correctly (i also tried  to install on a 20GB Western Digital EIDE HD and getting the same problem - this HD hasnt had any virus problems) and I've checked the boot order and that seems fine as well.

Barring the virus screwing up something I dont know about, could these two hard drives be totally fried?  I have 3 other Western Digital EIDE HD's (sizes 160GB, 250Gb &250GB) but these are for data storage only and have never been used for an OS (and frankly I cant afford to lose the data in an attempt to see if the problem would be gone using one of these drives).

Also, I dont have any floppies that came with these hard drives - I never ever needed them for anything in the 20 years now that i've been using PC's (and installing my own hard drives), plus the only pc with a floppy drive is the one I cant get windows on.

In the event that this is not a problem with some other part of the pc which I'm not familiar with, should I buy a new Hard drive from the store and see if it works then, or buy an updated windows xp set from a store keeping my older hard drives?

Thanks for taking the time to try and help me.