Disk boot failure

[Bobop]

The other day I was fixing the fan in my computer and I laid the computer flat on the floor. The problem is that when I turned it on at that time, I got a "Disk boot failure". I don't understand why, especially since it's a fairly new hard drive and I just formatted Windows XP on it. So I rebooted the PC and it loaded XP fine. It hasn't happened since and I ended up fixing the fan and I also changed the hard drive cable for the heck of it. It's a Maxtor DiamondPlus 10. So I downloaded Hitachi Drive Fitness (a popular hard drive diagnostic software) and ran some tests on it and it had no errors. I also ran Maxtor PowerMax and it says the hard drive has passed all tests and is certified error free.

I'm just so confused and a little puzzled on what to do since I'm not sure to install Windows XP again, buy a new hard drive, call Maxtor or what. The other thing is that in the BIOS I have it set to read from the CD-Rom drive first. Could it be possible that since the computer was layed flat that it tried reading from the CD-Rom drive and it's reporting that failure? Or would it be a different error message? Overall, I'm confused, and tired. Help me out.

 

[brinks]

So do you have a problem right now?
Or are you just wondering why that message popped up?

 

[Bobop]

No, I'm just concerned why it happened that one time. Right now it's working fine and I have rebooted several times for software installations without a problem after it occurred.

Could it be because of the CD-Rom drive, are they known to have problems when laid on their sides? There was no cd in the drive as well. How do I know if the disk boot failure came from that or the hard drive?

EDIT: Also, I wanted to mention that the Hard Drive at this time was set as Secondary Slave (during XP format, etc.). I have changed it now to Secondary Master. Could have this been part of the problem?