...this happened late one night so I left it alone till morning when I tried to power it up again. Again, it sounded the alarm and I pulled the plug before it went any further.
I opened the case and just looked around and saw a (second hand, from a friend's PC) bank of 256Mb Ram memory I had installed a few days earlier to be apparently not fully home. I pushed it home and also pushed home just just about every component to eliminate such obvious step from a basic troubleshooting sequence. I powered the PC again and this time no alarm sounded, all air coolers (power source, CPU and video card) and the HDD went to work and sounded as they use to do before break down. But nothing else happened. No boot-up sequence on the screen, nothing.
As this point I took my PC to my neighbourhood friendly PC technician, who tried pulling out every card (but the mother board) and replaced them, with equivalent cards from a working PC, first one by one , then in various combinations and eventually all at once, to no avail. He replaced all test cards in the "control" working PC to make double sure they were still ok after having served as "working controls" on the broken PC. This prompted his veredict as: "we have here a faulty mother board" which it very well is the correct diagnosis"

He finally "slaved" my PC's HDD on his good working PC to make sure it was operating, which it was.
Except for, HORROR OF HORRORS !

As on occasion, a visiting friend will ask to check his/her email o my PC, I had made up two (Windows XP) accounts. One for myself, at Administrator's level with full privileges, with a User I.D. and a password and a second account with limited privileges, without a password, for visitors.

As it happened, as a "slave" storage medium, hooked to a working PC, my HDD will only show and made accesible data stored in the "visitors, non-password windows session". No mention of my User I.D. partition is made whatwsoever, neither a sign-in windows is offered. It simply opens up already within the visitor's realm.

There is one folder named "User", which when clicked on, returns a small pop-up flag with the "Warning: Access Denied", which is surely where my own data is hidding. But no sign-in window is presented to access this partition.

Question: Does anybody know how to access I.D./password protected data stored in a Hard Disk Drive hooked to another computer as a secondary (slave) HDD ?

P.S.: When my HDD is hooked as the main (master) HDD to the working PC, after going thru the boot-up, the process is aborted at the point of showing for only an instant at the (Windows XP) sign-in window as it would in my PC.

Gosh, that's a dilemma. I can't help you I'm sorry but did wonder what happens if you boot up the computer in Safe Mode. Can you get to your Admin account that way?

Did the tech swap out the CPU to verify if it is good/bad vs the mother board being good/bad.

I had the same problem when i was having my PC problems and using my main HD as a slave.

If your MB & CPU are over 4 yrs old you might just replace them both- prices have come down a lot and speeds have gone up

I got a MB & CPU with most of the other stuff built on to it already- vid, sound, network, phone, 4 USB ports, firewire - i think that is most of it.
so no other cards to buy and my same wireless card was able to be used on it also.
I did get a SATA hard drive this time around.
about 150.oo for all that at our local owned PC parts store - they even mounted the CPU on the mainboard for me - so i just had to put it in the case and connect everything- which the book was very helpful.
faster , quieter, did I say faster LOL??

Would new MB+CPU boot up from old HDD¿?

I think I wore out my old HD when my system was failing- thought it was a virus at first so reinstalled XP and tried to save files - then that didn't work well so I installed some various Linux op systems to see what I liked compared to XP-- formatted and reinstalled over and over XP/linux etc- no matter what I tried sys kept failing and having issues til it totally died.

so that was when I gave up and got the new MB and HD.
Started form square one since old HD was more or less toast.

I don't know how to get around the password issue

How old is your system?

[Question is, he said, a new MB+CPU may not match the original BIOS+Windows XP software in which case I still could not gain access to my old HDD password protected data.]

Do you have a name brand pc?? - HP, Dell, gateway etc -- those do have proprietary OS I believe most anyway. HP for sure.

I know HP - probably most manufacturers - have a chat, email, or support section you can get information from them.
I ordered replacement OS from HP {for another machine I upgraded for kid} for only $18 - but turned out the MB was bad on it also we got a new non- HP MB, HD - so now it is just a generic and we can use our own copy of XP on it.

if you add a new generic {not the name brand} MB your proprietary OS will not work.

Hate to say this, but you may not be able to access the information at all. The files could be corrupted from the crash or the hard drive has bad sectors making it impossible for the cpu to read. Before buying a new mobo and cpu I would have the tech try a known working hard drive in your puter. If it fires up and loads windows your whole problem was the hard drive all along.

I just hope it doesnt cost ya lots of money to figure out and fix.