Firefox loads page at first start extremely slowly & while using suddenly loses its connection ability! How can I fix this?

Question

I'm using Firefox 4.0 I did all the updates I could, I didn't change anything except the history preferences and from advanced -> network
Whats happening:
I'm starting firefox, first time or second time I start doesn't matter, it brings every single page extremely slowly (google,facebook,mozilla.com etc)
after a while it loads the page, and after a little more while suddenly it loses connection and returns to first position
bringing pages extremely slowly
It's not about my internet connection, I have a good one and other applications using internet are working perfectly (including IE)
Add-Ons:
Java Console6.0.22true{CAFEEFAC-0016-0000-0022-ABCDEFFEDCBA}
Java Console6.0.23true{CAFEEFAC-0016-0000-0023-ABCDEFFEDCBA}
Java Console6.0.24true{CAFEEFAC-0016-0000-0024-ABCDEFFEDCBA}
AVG Safe Search10.0.0.1178false{3f963a5b-e555-4543-90e2-c3908898db71}
DownThemAll!2.0.2true{DDC359D1-844A-42a7-9AA1-88A850A938A8}

Answer 1

Thanks for responding, David. Using <Esc> and <CtrlW> might reduce the time in returning to the other tab, but does little when the triggering of a wanton alarm is very frequent. The connections I have used were extremely reliable and fast. I am using at this moment a 54 Mbps WiFi connection that lives up to its ratings in downloading & uploading data; yet, as shown in the attached image, I still get this worthless alarm. I do not know if this problem happens with my regular ISP since I have been using this tiny notebook only when traveling -- will test that once I am back mostly for curiosity, but even then if then the alarm were not triggered this would be of little consolation, since other browsers do not have the problem right now).
As a moderator, I urge you to ask the Mozilla-powers-to-be why there is no way to turn off the alarm with, say, a true/false switch in about:config (mind you, there is still old-versions junk in this config list, so it isn't we are talking about amending the constitution). Complains about this fugly alarm can be traced in the web as far back as 2010 at least. Besides, what is the advantage of the alarm for the average user? When FF users are still posing amazingly basic questions in forums of Firefox or Mozilla support, such an alarm ought to be _off_ by default and should be an option of advanced settings menu. This annoyance shows how much the critical focus on keeping a simple GUI uncluttered by trivial or higher-level messages still needs to evolve for Firefox, which I have used it since it was known a Firebird. Guess will have to switch to Chrome now while abroad.
Happy Holidays