As for the pagefile.sys, you were right... Thanks, now I'm glad I asked the other question, else I wouldn't have find this other tip! 16 additional GB of hard disk space make a BIG difference on a 80GB HD!! (SSD).
But I wanted to explain something that just happened to me and kind of "finishes" the story... Please, let me explain just in case it is useful for somebody else, some day.
My start point was this:
(1) 
My new situation is this:
(2)
As I said, the first thing I tried was adding two 4gb sticks to the existing four 2gb sticks at
(1). The two 4gb sticks appeared as "dimm slot" but not as "enabled slot" (there appeared 4096 on the first line, and a dash on the second one for both slots 5 and 6).
I don't know if this makes much sense, but I later realised that when trying to add just two 4GB sticks, I didn't properly insert the sticks at slots 5 and 6 - they weren't fully seated into the slot. I found this when I was removing them to continue to point
(2), and I was not in the mood for repeating the tests, rebooting, etc., so just forgot about the whole thing.
But today I came to think of it again, and added two of my old 2GB sticks (for a total of 20 GB) in order to see what happened... surprisingly, they were detected and enabled on my mother board. I forgot to take a picture, but the new 4 gb appeared as channel C. tRFC was 60 instead of 86 for these 2 GB slots (whatever that means), but everything seemed fine.
I was so excited! I was going to have 20 GB! Then I started Windows, went into control panel as a final check (Windows key + Pause/Break) and guess what... it said "20 gb installed, 16 available".
? How come???
To make a long story short, after pulling my hair for a while, I have just found out that Windows 7 Home Premium version (which I happen to use) is limited to 16 GB!!! You have to upgrade to professional, enterprise, etc. if you want more (up to a maximum of 192 GB). Arghh!!! I've always used professional/business versions of Windows, but when reinstalling a couple months ago, I thought I had no need for such versions and home premium would be fine for me. I checked for the upsides/downsides, but I didn't see the 16 gb limitation anywhere!!!! I wish I had read it somewhere, and that's the reason I'm typing this long message, I wish my experience helps somebody to avoid making the same mistake.
So, to summarize... I don't understand what happened the first time (existing four 2GB sticks + two new 4GB sticks). But it looks like four 4 GB sticks plus two 2 GB sticks work okay for the motherboard. Unluckily, I can't absolutely say for sure since Microsoft Windows spoiled my happy ending...
Anyway, at least I got the pagefile.sys and I have 16 GB which is enough for me right now. THANKS!!
