A computer, which was not booting from HD, shows now (after years not to be used) these messages:
"CMOS system option not set";
"CMOS displaytipe mismatch";
"keyboard error" and "RUN SETUP UTILITY. Press F1 to RESUME".

And now appeared a green thing in the keyboard's output and jumpers. Did it rust? If did, do I need to buy another one or I can 'repair' it?

A computer, which was not booting from HD, shows now (after years not to be used) these messages:
"CMOS system option not set";
"CMOS displaytipe mismatch";
"keyboard error" and "RUN SETUP UTILITY. Press F1 to RESUME".Has to be the CMOS battery died.

And now appeared a green thing in the keyboard's output and jumpers. Did it rust? If did, do I need to buy another one or I can 'repair' it?Yeah, I suppose it somehow rusted :/
You may try to clean it, carefully.

then use a q-tip with some WD-40 on it and swab those corrode'd connectors.

but the q-tip will not get into (don't pay attetion to this 'wrong English'. I don't have enought vocabulary and I don't practice...) the keyboard output. Can I use a small piece of cotton instead of q-tip?

Ah, yes, this msg should be at "CPUs & Motherboards", right?

post is ok here. Try spraying the keyboard connector (on the keyboard end) with WD-40 or similar electrical spray. Plug it in and out several times, but each time you pull it out, clean with cotton or q-tip saturated with cleaning agent, then spray again and re-insert several times. This procedure should clean the plug and receptacle adequately.

I have one of these kind of "WD-40", but it's "White LUB" and it doesn't show that it was made for eletrical things. Can I use it instead of WD-40? If not, what are the differences between them?

White LUB sounds like White Lube... a grease. No I wouldn't use that but rather something made for cleaning electrical contacts... you need something that cleans corrosion like Denatured Alcohol. WD-40 contains a cleaner with light lubricate that evaporates in a few hours. It won't make a mess like lube does.

Can you write some products that do the same thing as WD-40? (I'm looking for more options and in the internet isn't doing effect)

WD-40 is simply a product that cleans and doesn't harm plastics... something you must be careful of using as nearly all pc products contain plastic. The best substitute is Denatured Alcohol (which doesn't contain any lubricant or petroleum products). It's available at your local drug store and most hardware stores. Denatured Alcohol is not the same as rubbing alcohol but rubbing alcohol may also be used.

Here in the U.K. we call it isopropyl alcohol - good on tape heads, and no residue (Yes, we also have WD-40). There's a company called "Electrolube" which makes a "contact treatment oil", or "Servisol" make a "Switch cleaning lubricant". (I've found that one of these will attack some plastics - not sure which) Whichever you use, keep it to a minimum - any residue will attract dust, which in time attracts moisture....

Yesterday, I tried using (i think it is) a similar as WD-40 (ultra lub) and I did as Jerry K had said in the first time (pluging it in and out, in and out, in and out, cleaning after pluging out).

Result: no change.

What did I do wrongly?

(Here in Brazil, it calls isopropyl alcohol too. I wasn't sure that denatured was the same as isopropyl...)

Yesterday, I tried using (i think it is) a similar as WD-40 (ultra lub) and I did as Jerry K had said in the first time (pluging it in and out, in and out, in and out, cleaning after pluging out).

Result: no change.

What did I do wrongly?

(Here in Brazil, it calls isopropyl alcohol too. I wasn't sure that denatured was the same as isopropyl...)
Let me clarify something here: DENATURED alcohol is NOT the same as ISOPROPYL alcohol...

RUBBING alcohol is another name for ISOPROPYL alcohol; "rubbing alcohol" contains MINERAL OIL, so that it can be used EXTERNALLY on skin. It is called "rubbing alcohol" because the oil in it lubricates skin, keeping it from being dried out and irritated by the alcohol...

Do NOT confuse DENATURED alcohol with ISOPROPYL alcohol; they are NOT the same product...

Good luck cleaning those connectors...

Yesterday, I tried using (i think it is) a similar as WD-40 (ultra lub) and I did as Jerry K had said in the first time (pluging it in and out, in and out, in and out, cleaning after pluging out).

Result: no change.

What did I do wrongly?

(Here in Brazil, it calls isopropyl alcohol too. I wasn't sure that denatured was the same as isopropyl...)

hug,
I don't know as you did anything wrong... but if you cleaned the problem connector and it still doesn't work, there is nothing else you can do other than perhaps replace the problem device. If you removed all corrosion from the device and it still doesn't work, there is no miracle fix that I'm aware of. Normally, corroded connectors are simple to clean and doesn't require much skill or know-how in order to accomplish. I try to use a stiff brass bristle brush when I can and shine those dirty connectors up a bit. But sometimes the corrosion is in a place that's difficult to get a bristle brush into. In that case I just use a small scraping tool like a small blade screwdriver under a magnified/lighted glass so i can see it better. And where applicable, I use a small piece of 800 grit sandpaper in combination with small tipped forceps and can usually get a large percentage of the corrosion off. It's not normal for connectors to corrode since most are plated with nickel, brass, silver, or some other non-corroding metal. For the fact that it is corroded indicates it was in the presence of some kind of acid. Once that metal plating is gone, there's little you can do to prevent further corrosion except by keeping it coated with some kind of oil product. Just be cautious with the amount used.