Does the BIOS correctly detect the HDD you're attempting to boot from? Since your FDD is working fine, you should make a SeaTools DOS Bootable diagnostic disk and test your drive using this tool. If you go to Seagates website, you'll be able to download that utility. Once you've made the bootable SeaTools DOS disk (using a computer which is definitely not virus infected), write protect the floppy before using it on any other PC. IF these problems are the result of a virus then you should be able to zero-fill the drive (which effectively wipes the drive totally (including any partitions or remnants of partitions). You'll effectively be restoring the drive to as close as possible to a like new state. Test the drive fully and see what Seatools gives as the result - there's a manual which covers use of the tool on the same website - research it and understand what you're doing before you start.
Thank you for you prompt reply. I've had the PC and mobo sandwalled just in case, so nothing could contaminate in case of MBR virus. However, I can DOS boot from a write-protected floppy (Win98) or even WinXP bootable CD, and access the drive normally, just can't boot from it. The drives are normally showing in the BIOS, including the old IDE or the new SATA drives.
I could boot from CD and fully install XP on the hard drive. I am now testing with the old IDE drives to simplify the process. Drives were tested and working normally in another box. Reboot from the hard drive always fails, even after normal Win98 FDISK for single boot partition and Format /S/V/U. When I booted from XP CD and did fresh install of XP, reboot failed. When I ran FIXMBR after rebooting from XP CD again and running repair, I was able to reboot fully to XP once, but could not reboot again from the hard drive. I'm still trying to isolate something more specific, other than "can't boot from hard drive for either XP or older Win98 DOS boot". Just to be safe, I'm isolating anything coming in contact with the hardware. I've tested the board fully bare (CPU, memory, no other drives including DVD burner, just floppy and single master IDE drive) and simple Win98 boot format, with no success. Is there something documented that could block hard drive boot ? Or is there still a possible BIOS corruption ? I have other test hardware parts available, so any suggestion would be appreciated. Thanks again.
This is all well and good but just because the drives boot in another PC, that does not rule out any problems with them - some PCs are more 'fussy' with drives than others - eg spinup time issues may be handled differently by some boards to others. What did Seatools testing come up with? Have you zero-filled (any of) the Seagate drives successfully? Have you had a look at the Seagate website and downloaded the tool and manual yet? Other drive manufacturers may have similar tools on their websites so check them out, depending on the other drive makes and models.