Ok, I managed to solve more or less my problem. SO when it first happened I thought is a virus/malware and I cleaned my system but the problem remained. That is when I tried settings and other things suggested online (nothing helped of course). I suggested it is either my fault, so I tried FF in safe mode with all add-ons disabled - same problem. Then a thought came that maybe the program is damaged.

So What I did is I removed FF with Your Uninstaller 2010 because it removes everything, all hidden files and registries. But I decided that I don't wanna waste more time (if I have the same problem) with ver.6 and made the clean installation with ver.4. Now I'm working fine online. Everything loads nicely.

So this is my decision. Maybe in a few weeks I'll decide to update on ver.7 (when I all the add-ons are compatible.)

Please if this or any other decision worked for you share it for the general public.

Also If anyone tried the same approach but installed the same ver. (6.0 or 6.0.2) please let us now if it is all fine.

This morning my FF decided to update itself without asking me to 7 and the problem was still remaining. Again using v.4.