Question : Problem: Is it the keyboard or the motherboard?

A friend spilled coffee all over her Dell Inspiron 300m notebook computer. It appeared that the thing was hosed. She sent it back to Dell and they said they fixed it by putting in a new keyboard. When she got it back, it had the same problem. Some keys on keyboard did not work at all, some spewed out triple letters. She got her money back from Dell and I volunteered to take a look at it for her.

I pretty much concluded that the keyboard was still the one that the coffee got spilled onto. Close exam with a magnifying glass showed crud on it, and it seemed to me that the "a" key stuck a bit. Also the space bar "didn't feel right".
When I turned on the computer, it beeped furiously. The "alt" key on the left of the spacebar stopped the beeping. Trying to type into Microsoft Word gave very strange results, mostly, as stated for the original problem, triple chars when one key was hit and other keys not working at all.

I managed to run AdAware, SpyBot, SpyWareBlaster and AVG. No problems were found but the definitions are several months old. I couldn't connect the pc up to my wireless net because I couldn't type in the key!

Since I had nothing to lose, I removed the keyboard and soaked it in hot water to remove the crud. I let it dry for several days. Now all keys have an consistent touch and feel so I think the crud was removed.

I put the keyboard back in and turned the pc on: no beep beep beep at startup anymore. But the keys still don't work. Different symptoms though: lots more keys don't work at all. A few do work. Others spew out two chars. But nothing is consistent.

What is very puzzling is that the keys behave differently depending upon what app I'm using (Notepad, Word, Excel). Why would this be?

I did order a replacement keyboard, hoping that that really was the problem. I just put it in, and turned the pc on. I get the beep beep beeeeeeeeeeeeeeeeeeeeeep at startup. And NONE of the keys work.
Of course, it could be that this "refurbished" part is also bad! But how would I know?

I don't have a USB keyboard to plug in to the notebook. All my keyboards are PS/2!

The touchpad does work.

I know it's possible that something shorted out on the motherboard. Do I have enough conclusive evidence to suggest this? And that the keyboard is not the faulty part? Or it's not a virus or something else?

Thanks!

Answer : Problem: Is it the keyboard or the motherboard?

The way to be 100% sure is to connect a USB keyboard.  Should be able to purchase one for under $10.00 or borrow one for testing.

What about touchpad (mouse)?  Will apps open and close normally?  If so, chances are good that it's either keyboard or keyboard connector.  Those ribbon cables are tricky, so ensure that cable is properly seated in motherboard connector.