Please help me. I have an older HP Pavillion XT868 tower. The hardware config is as follows:

AMD Athlon 1200MHz
256MB RAM
80GB EIDE Maxtor HDD
64MB ATI All-In-Wonder Pro 7500 AGP
Conexant 56K V.90 WinModem/Audio Card [these are half cards that connect with an internal cable](actual PCI cards-not onboard)
on board Realtek RTL 8139 10/100 Ethernet
HP branded (Pioneer) 16X DVD ROM
HP branded (not sure of real manufacturer) 8 X 4 X 32 CDRW

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Now that the hardware is out of the way, on to the problem.

My O/S configuration was 40GB for WinXP and 40Gb for the Fedora Core 6. That was broken down as 1GB for swap partition and the remainder for the standard files, user files, etc. I had Boot MAgic 7.0 installed as the boot manager which in case anyone is not familiar, it not only overwrites the MBR, but also it writes files to windows including registry files, etc.

Recently I had a nasty worm that went all through my windows partition and caused havoc. After running virus scans and taking care of the little pest, I thought everything was safe. I did a shutdown in windows and was going to reboot into fedora.

After the reboot, not only was windows completely messed up, but so was my MBR!!!!

I tried to reinstall fedora, but I keep getting the error I/O error, cannot write to sector 0, cluster 0.

I tried to reinstall windows and got the same error message.

The partition tables are non-existant and the hard drive is completely useless. I took the PC to Future Shop (similar to a BestBuy or Circuit City for those of you who don't know what a Future Shop is) which is the closest thing that we have to a "technology store". Anyways, they told me that linux is a horrible horrible operating system that is nothing but one big virus. After giving the so-called A+ certified tech an earful and educating him on the true powers of penguin computing, I explained to the store manager that I don't feel I should pay for a diagnostic service that was not ever performed. Thankfully she agreed with me. I took my paperweight err I mean PC back home and it is still in the same non-usable state.

I tried my HDD in another tower with the same IDE cable, and the same error occurred. I tried another HDD with a different IDE cable in my tower and it worked fine.

I tried switching the HDD's and IDE cables around but neither worked when switched.

I am totally confused and frustrated. If anyone has any ideas just short of taking the PC to the local firing range and using it for target practice, I would love to hear from you.

Thanks to everybody in advance for the help.

You probably need to run a low level format on the drive using the manufacturer's hard drive utilities. These days, a low level format is really a zero fill, i.e. every sector of the hard drive is written with zero, which leaves the drive in the same condition it was in when it left the factory. Of course, this will destroy all data on the drive but sometimes this is the only way to bring back a drive with a badly corrupted mbr.
You can download the maxtor hard drive diagnostic utility here:

http://www.seagate.com/ww/v/index.js...00dd04090aRCRD

Also, check out the pdf file for details on how to do the zero fill and how to run the other diagnostics.

You can also try zero filling the mbr yourself from within linux if you have a good linux livecd like knoppix. Just put the hard drive in your box, boot of the livecd and run as root:

# dd if=/dev/zero of=/dev/hdx bs=512 count=1

where "x" corresponds to the device file for your damaged hard drive. This will zero out your mbr, i.e. it will right zeroes to the first 512 bytes of your hard drive which is the first sector, the mbr. This is a lot faster than doing a full zero fill of the drive and may do the job for you.