HI, AND THANKYOU FOR TAKING THE TIME! History: P11 266 using 40gig Maxtor hd that was partitioned with partion magic 5 into 3 partions (c:6gig D:8gig E:25gig) running win98se for a year or so. upgraded to win 2000 installed on C: drive changing files system for c to ntf. left d and e the way they were. got virus!... lots of trouble! Crashed hard! would not reboot. could not boot up on startup disk.. said disk io error... all versions of boot disk gave me disk io error. so put partion magic emergency boot disk in....it worked allowing me to put C: back to fat32 the same as it was... seemed to work. But boot up to hard drive failed but thats when bios stopped seeing hard drive. I have now used all diagnostics available to me to no avail. updated bios to make sure. put in another hard drive and it booted perfectly. Got new ribbons, rechecked jumpers and pins. used maxtor hard drive utilities to boot up computer .. it found the hard drive and brought up these errors. smart enable command failure, bios extension support failed, partition information read failure, ERROR CODE S01 drive recal test failed smart disable function failed ERROR CODE UK0E02 ADVANCED DIAGNOSTICS.. LBA 0 BLOCKS 0 HEADS 16 SPT 63 MAXIMUM LBA 0 CONGRADULATIONS HARD DRIVE IS NOW ERROR FREE AND RECERTIFIED. Bios does not see hard drive, cannot use Fdisk or Fdisk /mbr cannot put sys files onto hard drisk. used debug to remove all hard drive info.. used debug to remove all dos partitions used debug to remove all non dos partitions and clean hard drive completely. I am determined but as you can tell I really do not know what to do... ANY help would be so appreciated... It would seem that the actual drive is fine, but the io or start up disk info is gone and cannot get it back on. Thankyou for any advise you can give me..