i have a Compaq Presario s4000v. Everything was working well, then the machine was turned on one day and BOOT DISK FAILURE was displayed after the post. i tried a known working hardrive in this machine and it booted up fine. Now, the first drive is set to master and i got the boot disk failure message. when i removed tha drive and put another one in, on the same channel with the same ide cable, it was on cable select. is the first hardrive dead, meaning that there are to many sector errors that it just cant boot and displays the Boot Disk Failure message? Also, with the first drive, i booted to an XP cd and went into recovery. When i got in the console it said that "This drive is an invalid drive letter" and it displayed C: with the the underscore next to it. so i tried running chkdsk /r (i knew it would work though, because of the prev message) and i got a message saying that it could read from partition. So im left with the assumption that the hardrive is bad and needs replacing, but im not sure. Any more info would be much appreciated. Thank you.