Hello.

I am currently in the process of moving some files from an old 420 MB hard drive to my main drive. I finally was ABLE to get both drives recognized (by USING separate IDE cables for both of them). Installing the drives, however, required removing the processor's (P4 2.0 GHz) heat sink, and then (of course) putting it back. Unfortunately, I now have the problem of my machine automatically shutting itself off. This began earlier today after a separate attempt at putting the 420 MB drive in.

What happens is the machine automatically shuts itself off (I'm assuming the motherboard / BIOS is doing this as some kind of a protective measure), usually during Windows loading, sometimes very shortly after, and other times before even beginning to load the OS (such as in the BIOS setup). The event log shows the error as "Pre-boot Error: Keyboard Not Functional", and indeed the keyboard QUITS working right before the shut-off, even though it works fine otherwise, and the same thing happens without anything plugged into the PS/2 slot. Also, the CPU fan seems to speed up or at least get noisier, which brings me to my next point - one of the fan WIRES is broken (I think it's the ground, though it might be the tachometer). However, simply disconnecting the CPU fan (yeah, I know, not a good idea) and trying to boot with it off produces the same result! Also, earlier today after it started working again, I believe the wire was severed also.

Anybody have any ideas on what to do? Thanks!

EDIT: The machine does the same thing with the IDE and power cables to the second (420 MB) hard drive disconnected).

EDIT TWO: I was able to get into Speedfan right before the machine shut itself off. CPU temp was normal (35 I think?) but remote was at 102! However, this does not seem right, as nowhere in the machine felt hot. I have had this same computer get so hot it caught on fire (problem then was a clogged PSU fan), but back when it got hot then you could feel the heat very well on the chassis. Now the computer feels very cool all over, so I'm wondering if it's a sensor malfunction.Quote

Also, the CPU fan seems to speed up or at least get noisier,

Now the computer feels very cool all over, so I'm wondering if it's a sensor malfunction.

that is due to the motherboard receiving high temperatures from the temp sensor underneath the CPU, and in turn, making the CPU fan increase speed in hopes of dissipating that heat. it sounds as though you may have incorrectly hooked up the heatsink, having a fan with a severed wire also doesnt help. is the heatsink seated properly and securely? did you remember to apply thermal paste? if so, did you add the correct amount of thermal paste?