First of all, thanks for your comment, you really raised some good points!
However, I will not be able to answer all your questions, because, like I
said, I already reinstalled Trisquel, deleting everything that I had in my
HD. I would not have done it if I had another computer available, but right
now I only have one available and I need it working. =S I would have prefered
to investigate it deeper, but it really was not an option, I needed a
solution =S
However, I will try to address all your questions one way or another:
I did not try safe mode. It was one test that I did not thought of. My
mistake.
One reproducible thing would be "Everytime I connect to
"https://startpage.com" it will drop the lock and the "s" and redirect me to
"http://startpage.com/#" Notice that it adds the # symbol". Another would be
the fact that the green bar in hotmail would also disappear, but I couldn't
notice any change in the url. HOWEVER, it wouldn't happen if JS was disabled,
so, I can pretty much be sure that JS was being used to do the trick.
However, it was happening in all websites (duckduckgo, startpage, hotmail,
trisquel, etc).
I was using https everywhere addon and noscript addon, so it should not
happen. Also, if the connection to https was somehow damaged, it should have
given me the "this connection is insecure" kind of thing alert. That never
happened, the browser was acting as if it was all too normal.
I am using my computer, the same one I have always been using. I did not
install any certificates. Also, I was not using wifi at the moment, so a
"typical" sslstrip attack is unlike. More likely, something got itself inside
the browser/system and started running malicious JS.
The only thing I installed was Linterna Magica, Lightspark and Gnash. I was
testing if having those flash players would improve my browsing experience.
HOWEVER, I did not noticed that behavior right away after installing those. I
still have to say though, they did not improve my browsing :P I am sticking
with html5 lol.
I hope some of this made sense to you. I thank you again for taking the time
to write the comment, and I don't think those were dumb questions. I actually
thought it could be my ISP but I proved it was not. I thought it could be
hardware, but it proved not to be so.
I can't really know WHAT it was anymore, as I installed a fresh new version.
But, I still think I did the right thing alerting the community. Whatever the
reason was, if it affected my system it could affects others. So... just keep
an eye, and if someone notices anything, post here!
Thanks again =)