I have had the strangest thing happen to me this past month. My computer just went blank on me and I could not reboot it. I took it to my local tech shop and he said he could not figure out what was wrong and ask me to bring in the monitor I used with the computer. Three days later he call back and said it boots up and charged me nothing. He did say however that some times the computer will act that way IF the hard drive is about to go out. I know very little about the tech side of computers but I was thinking maybe the power element is bad, it was custom made and it is running 600 watts of power. It does not happen that often but I wanted some one else to weigh in on the problem.

It is next to impossible to diagnose intermittent problems. A tech needs to catch them in the act.

However with hard drives, modern drives actually store information on the drive which indicates the health of the drive. While not perfect, this information can give you a hint if the drive is in danger of imminent failure.
For example, WinXP has via Control Panel an Administrative Tools selection which includes Computer Management. This permits looking at your hard drives and might say something like:
"WinXP System NTFS - status Healthy."

More specific information can be obtained using diagnostic programs supplied by the maker of your hard drive.
Third party programs such as AIDA32 can give very specific information about your drives. This program can give you, for example, a raw read error rate or seek error rate and might say OK value is normal.

lexxy-Are you sure it was the whole computer that died or just the picture on the monitor?
This same sort of symptom happened to me and it was the connection on the back to the monitor.

Geo,

You may be right however I don't understand why the tech could not figure it out w/o my monitor being used. I will double check now that ALL connections are secure. My friend had this system made for him and later sold it to me and he has assured me that it never happened to him so maybe you are right......user error. Thank you and Robert for your help.

Lexxy, he may have wanted your monitor to make sure the monitor was working properly.

If this happens again, one way to rule out the monitor is to use another monitor you know works.

If it occurs again, listen closely for any BIOS beep codes, they'll give you a clue which component failed during the post process.

If there are none, I'd suspect the video card, cable or monitor before I'd worry about the hard drive.

That's nice to know Inland. I'd not heard of this before, which got me curious, so I Googled BIOS beep codes and found this BIOS beep codes information site. Hope this helps others who are also curious.