PC completely DOWN (No Power + nothing)

Depends on the OS you are using.

What happens when you unplug the power cable from your PSU and plug it in some minutes later again? I had that problem too, the solution was a weak power supply.

For your question regarding plugging your HD into another computer i have to agree with coral. If you have WinXP, Win2k or Linux, it is very unlikely that you can just plugin and fire up without making changes to the OS, except if your second computer has about the same main components as your first (concerning Processor, Mainboard, RAM).  Win9x or WinME however should run fine also with changed Hardware.

fine as sand it will work may need to adjust the jumpers on the hdd i dono what  it is going into as i presume it was a master goig in to be a slave but i dono

try checking out the compenets in another pc

Some things that will keep your machine from booting and showing even a BIOS screen:

- inadequate or faulty power supply
- faulty video card
- bad RAM
- bad cpu
- bad motherboard

You can try to isolate the problem by changing one of these at a time.

If you really need to get to the data, you can hook up the drive as a slave in another system, but bear in mind that a FAT32 system can't read an NTFS drive.

Do you get any beeps when you first power on? Are you saying it does power on, then turns off? It might be the memory, but I suspect a bad motherboard. You could power up without the memory installed to see if thats the problem. It's kind of strange that it just stopped on you like that. I've sort of had this trouble with my PC, but fixed it by either clearing the BIOS or unplug PSU cable to board. The clear BIOS has a jumper, but I remove the battery (old school way). I disconnect the power to board, then pressed power switch, plug the power to board. I do this to clear  some left over power in the power supply. Do you have a UPS like APC for backup power? I would advise to get one now if you don't have one.

I just have tried your advices, but it's nothing happen even a beep, a light,.. just 2 fans for 2sec. That's all.

I used Win2K for long time and I just installed WinXP Professional to it about a week.
My system is NTFS drive.

I thought my motherboard or CPU is bad. I make sure it is bad before I'm going to buy new one.
Anyone have any other idea for this problem?

Can I upgade my system by replacing the motherboard and CPU to Pentium 4 3.2GHz with using all the other old components/devices.

Thank you very much for your advice.

Once you have eliminated all the other possibilities and the all that is left is the motherboard, then it is probably the motherboard.  Have you tried swapping parts in?  The cpu can be tested if you can install it in another system.

You can replace the motherboard and keep everything else by doing a repair install, and you will still have your programs and data: http://www.dougknox.com/xp/tips/xp_repair_install.htm 

I would like to make sure the motherboard or CPU which one is bad. How can I test it? Do you have any method to do; please help me out step-by-step. I don't know much in PC. I'm greatly appreciated.

Thank you very much,

And I have only 1 PC. That's the problem.

Thanks

Both are very complex equipment and virtually impossible to test fully w/o a spare system.  Can you borrow a cpu from someplace else?

Thank you for your advices. But I can't borrow any CPU from anyone else I know, because no one use CPU (Socket A).
That's the problem.

Can I use my old SDRAM to DDR system?

Thanks again!

What is the PC rating of the old RAM?  What was the speed of the AMD cpu?   A P4 3.2 system will require 800 FSB setting and PC3200 RAM for optimal performance.

Thank you all!

JimLe115, my comment above T_Le's says the problem is the motherboard, once you have eliminated all other possibilities.  Can you explain why you accepted his answer?