Acer Aspire 7520 and 7720G keyboard problems

Today I decided to clean my mother's Acer Aspire 7520. I cleaned the display, keyboard and removed dust from the heat sink. I used ethanol (70%) to clean the outside of the laptop (just like I did many times before).
What surprised me this time was that after putting cover back on and installing battery, laptop would detect only 86 MiB of ram. I opened it again and tried to see what could be wrong. I removed ram module from the top slot, and laptop detected 1 GiB of ram (it has 2*1GiB).
When I put the top ram module back, it would again detect only 86 MiB.

At that moment I panicked and I didn't know what to do. I again inspected the laptop, mostly to calm myself and think of something to do, and noticed that there was a little bit of ethanol which didn't evaporate on the keyboard between keys. So I removed key caps and cleaned that little bit of ethanol up.
After that I turned laptop back on and it detected whole 2 GiB of ram. At that time I noticed that keyboard wasn't working (it was working fine up until now) . I turned the laptop off, and waited for a few minutes, thinking that maybe there was still some ethanol that didn't dry. Still the keyboard wouldn't work. So I took keyboard from my Acer Aspire 7720G (they use the same keyboard models) and put it in the 7520 (I first took a little thermal pad that was on 7520's keyboard and put on 7720's keyboard). I tried to dry the keyboard with a hair-drier, but it didn't work.

Do you have any tips for this kind of situation?? Anything else I could try, before buying new keyboard??


Also I noticed that the PCB with Caps Lock and Num Lock LEDs on 7520 looks like it is rusty(??) when compared with one on 7720. Is that normal? It is still working.


Both laptops are still in warranty, but the 7520 was bought by a company in my country, and its ownership was transferred to a company a neighbouring country for which my mother works. It was then assigned to her, and she uses it to work from home. So it is much easier for me to get my own laptop repaired than hers.


EDIT: Well, I just took the keyboard apart. Under the keys there is a thin plastic layer with rubber cups on it. Under that there are two layers of transparent plastic which is transparent and there are circuits on it. Knowing that any liquid between the layers would caue trouble, I carefully inspected them and noticed :
1.That there isn't any ethanol between the layers (this was a problem on some desktop keyboards I have)
2. The two layers are welded together on all edges, so there isn't any way that liquid could get between them.

I am surprised to have found this out. I thought that the reason the keyboard died was ethanol (I use it because you can't easily buy 2-propanol, which is as far as I can see almost always recommended on net for cleaning, here and because it evaporates quickly), but now I have no idea what had happened.