Computer does not recognize bootup disk

[bullwinkle]

Good Evening,

I'm trying to get an old computer up and running.  It used to work until some construction guys did some demolition in the adjoining room.  It seems some substance has affected this PC.

I did a thorough cleaning of the hardware but with no result.

When I boot up the system claims that the hd is unbootable.  I substituted a hd I know is bootable and got the same result.

When I look into the BIOS it seems not to be able to automatically find the hd.  A manual setting makes no difference.

I'm thinking the mb has a problem.

What do you guys think?

AMD 3400+ CPU
MSI K8N Neo2-FX mb
1 GB memory
nVidia 6800 GT video card

[Geek-9pm]

You have to clean all the dirt out of all the connectors.
You can use Alcohol (70%)as well as compressed air.
I some cases only alcohol can lift out the crud.
Most of the time it is the flat cable  connectors that get filled with crud in a dusty environment. Inspect the connectors with a magnifier glass.
Make sure is is dry before you turn on power.

[JJ 3000]

Try a different data cable. Check you jumper settings.

How did you clean it? Did you ground yourself to the case? Static electricity can fry your circuit boards.

[bullwinkle]

I've built many computers, including this one so I know I didn't fry the board.

I cleaned it by removing the boards and blowing air into all crevices and crannies.  Also taking out the dust bunnies.

When I first tried to start the PC, I'd get a flash of power and then everything would go dead.  So I replaced the PSU and it ran but failed to recognize the hds.

The hds are IDE.  So I disconnected them and connected a SATA drive.  Same result.

So by actually using different cables there was no change.  Hence I don't think the problem is in the IDE cables which is why I suspect the mb.

[patio]

It will do this if standoffs are not installed/missing...
Did you use them ?

[Karnac]

Gypsum dust from drywall is a killer....

http://www.sunmanagers.org/archives/1993/0510.html

[bullwinkle]

Standoffs were installed initially and have not been tampered with since.

The fact that a new hd (the SATA one that was not exposed to the dust) could not be recognized by the BIOS indicates to me that the problem is not in the hds. 

With respect to the rest of the article, the problem began the day after dry wall was installed which meant that if overheating of a circuit did occur, it happened in a relatively short amount of time and probably to the BIOS.

I can't think of another answer than to replace the mb - if I can find one like it.

[Geek-9pm]

When I look into the BIOS it seems not to be able to automatically find the hd.  A manual setting makes no difference.

What does it recognize? Is the memory OK?
Cab it boot a floppy? Does it even try?

Have you washed out all HDD connectors with Alcohol?
As another mentioned,. dry wall dust is really bad  electrical connections.
You have to get it all out.