CPU seems dead, but HD is trying to boot

Hello, everybody!

Can not figure out what is going on with my Asus motherboard.
It used to work fine in the system I have built a month ago until I have tried to add a second IDE hard drive. OK, I accept the blame. The question is how great are losses and what I may hope to recover.
Motherboard A7N8X Deluxe shows sign of health before power switch is pressed on. When PC is powered on - all fans are running including one on the CPU. Green light on motherboard PWR_LED stays, but no signal to monitor. Can not power down PC by pressing the same button on front panel which turns PC on. No beeps even when memory is removed. Heatsink seems at home temperature after more than 1 hour run.
But! The hard drive I used specifically to test this mobo started to make sounds as if it was going to boot, and it even clicked once as if it succeeded. I tried several times - HD kept puffing like it was trying to pull a train. Without video signal it is hard to tell, but ~400 MB HD definetely was trying to kick DOS in. I installed another A7N8X Deluxe mobo in the same case (this time with another tested working processor) and with the same memory and video card, but with another PSU providing more amper on +5v rail. Now the same HD booted to DOS.

Question: is it possible for HD to start booting even if the processor is apparently dead?

If not dead, I would have to go through the chores cleaning the thermal paste - and since I am not comfortable with this idea - another question.

Is it possible to remove CPU together with heatsink and fan without dismantling CPU/heatsink?

Thanks for reading and possible solutions if any!

 

On your question about whether you can take your CPU out without dismantling the heatsink,

It depends on whether or not your CPU is one of the socket 370's (or older) or the newer ones. The socket370's and the older ones have a smaller heatsink fan block so that you can release the whole thing at once.

However, on newer machines, the heatsink is very big, and you cannot release the CPU without taking the heatsink off. However, I did manage to pull my CPU with the heatsink together while it was still locked down. Note that I did not do that on purpose. I was going to clean out my heatsink, but Compaq uses crazyglue or something to lock down their CPU. I eventually managed to get the CPU off with a few drops of GooGone. I don't advise you to pull out the CPU and heatsink together if you are using one of the newer CPU's.

 

If the computer doesn't activate the monitor since the addition of another hard drive, I'd say it's the hard drive that's causing the problem. Have you tried disconnecting the hard drive to see whether it makes any difference ?

 

Thanks for reading and commenting!

Just for reference:
a) A7N8X mobo has socket A/462 and the zero-force lever is obstructed by heatsink. So, I got the message: the only way removing the CPU - dismantle the assembly.
b) 420 Mb HD used for testing the failed system was not the one of HDs that I have tried to make work together (one 20 Gig DMA 33 - master, another 80 Gig DMA 66/100/133? - slave, both Western Digital and worked fine alone when configured single master).
What concerns CPU/motherboard combo trouble - I went step-by-step disconnecting/removing either one piece of hardware by one (and testing the effect with PC Analyzer PI0050E) or almost anything at once leaving only the power from main and 1 stick of memory.
The result was the same - no beeps, no video signal to monitor, and PC Analyzer LED display showing code 7F. The seller of PC Analyzer was so kind as to ask the Chinese manufacturer on my part and gave me the following answer. "About trouble code 7F. It usually means the same as code 0D. Because this code is rarely displayed, it is not printed in the manual. And this code indicates your video chip has problem."
Now, as I installed the same Video Card into the second mobo (again A7N8X Deluxe), and it proved to be working fine - I ruled out the code 7F/0D explanation putting blame on video chip. BTW, when used on a good A7N8X mobo - PC Analyzer displayed code 2524 when booting and stayed till power shut down, just as on another good computer.
This stick of memory worked fine too with another - good A7N8X mobo.
Prior to swapping motherboards I removed a pair of extra stand-offs (possible cause of my system failure) under the failed(?) mobo and proceeded testing the failed(?) with mentioned result - code 7F, no beep, no video.
c) I changed also the PSU when I checked with a good A7N8X mobo. Dynex DX-400WPS was not providing enough amp on the +5v rail (Asus recommends 30A, against Dynex's recorded 28A). But this explains only why I initially failed to boot 420 Mb HD attached to the good A7N8X mobo, but succeeded after swapping PSU.

The question: is it possible for a HD to start booting with failed CPU or mobo, and if one of them might be good, how to find this out with least expense?
Taking this combo to PC repair shop makes no sense to me - kills the fun of learning on your own or somebody's errors.

What are your opinions?