Thank you for your replies guys but they don't add anything over what I can google and did google before.
According to one topic I've read before, UXTerm does not add Unicode to XTerm because XTerm can process Unicode strings itself. I don't know if it's true or not.. just for your consideration.

Maybe I should ask another question.

Why are XTerm, UXTerm and LXTerminal all included in this distribution if difference between them is so insignificant? Why not include best of them? There is only one text editor, only one calculator, only one graphics editor, only one file manager.. included in distribution.  What is the reason to include 3 terminal emulators?!

Why not just use Chrome for GA then?

I explained it before. I need two browsers. One for my regular Google account (with mail, drive etc) and another for my GA account. I prefer to have them on separate browsers then to switch accounts over and over again.
On Windows I use Dragon (by Comodo) which is Chrome clone

Have you tried with Chromium?

I haven't but I've read, that Chromium is simply Chrome stripped of most add-ons so I dodn't believe it would work. I have to give it a go.

I tried the browse of Google Analytics in Iceweasel of wattOS R8 LXDE. A result was normal.

I've got 3 accounts on GA and one of them renders normally most of times but two others never do so this behavior is not so straightforward.

Probably the add-on that teedee add will be the cause of the problem.

What add-on do you mean? I didn't add anything.

I think it is significant, that on 3 browsers Iceweasel, Firefox and Opera this problem looks similar. Although Iceweasel is a child project of Firefox, Opera is different but still they suffer the same problem. Chrome is different what doesn't surprise me because it is Google's child and it would by surprising it wouldn't work.

It must be some add-on missing, that causes a problem but I have no idea how to investigate it?

I'm happy being able to help you! and thank you for posting working solution.

This makes another prove for me to test the simplest solutions first. Sometimes things break by themselves and we connect wrong dots leading to wrong conclusions.

I call it "fly effect" because it recalls an old joke about a scientist testing a fly. He put a fly on a table and commanded it to go.. so fly walked and he made a note "after commanded to go, a fly walked". Then he removed one leg of it and commanded it to go again.. fly went so he made a note "after removing one leg, fly went". He repeated observations one leg after another until a fly has been left with one leg only. Then he commanded it to go and fly went with a lot of effort.. so he made a note "with one leg left, fly hardly went". Finally he removed sixth and last leg and commanded fly to go but it did nothing. Our scientist made a note of observation "after removing six legs, a fly became deaf". 

Thanks BALLOON. It's not exactly what I wanted but it works at last
And mtPaint is pretty nice as well.

It's as if it's starting to boot from the USB and then something disables it.

That is good point I believe. So the problem is not that it doesn't boot up from USB but something happens afterwards.
Next bunch of questions/suggestions
- does it happen on all USB ports? some pc's prefer one port over another to boot up
- have you tested USB port you are booting from?
- have you reset BIOS settings? I know you didn't touch them but it is always worth a try to do hard reset including battery removal

Booting from USB shouldn't be affected by any installation on HD because it happens before even single bit is taken from HD.

Don't feel offended but still most of problems like this come from simple errors or coincidences so you might have already tried my suggestions.

I would try:
- checking BIOS settings especially USB enable/disable
- checking boot order (USB should be before HD)
- testing USB stick on another PC

USB sticks fail from time to time, BIOS batteries also.

How do you know, that you cannot boot from USB?
What do you want to run from USB?