I was fooling around with my computer which has Windows XP Pro on it, trying to add an extra hard drive as a slave, but to no avail. After I gave up I loaded my computer normally, only to receive the message "disk boot failure, insert system disk and press enter". I didn't change anything on the master drive whatsoever, yet it gives me this message. When I go into the BIOS, it doesn't even recognize a hard drive even being plugged in to the master IDE, yet the CD-ROM drives are recognized. I've tried different harddrives, different IDE cables, and jumper positions, but it doesn't seem to want to work at all. The actual harddrives I plug in power up, but the computer won't recognize any of them. The computer is custom built with a Pentium 4 with a 160 gig Western Digital harddrive and 700 and some megabytes of ram. Any help on this problem would be much appreciated.