I get message when attempting to access many websites - unrusted connection, please help

Question

I have been accessing many websites via firefox for many years, but over the past3-4 days I have been receiving the message - untrusted website, with the technical details informing me that www.google.com uses an invalid security certificate because no issuer chain was provided. I have uninstalled firefox 31, and replaced it with No:30, but it has made no difference because the problem still persists in this version as well. I have tried going through chrome and yahoo to those same sites but I experience very slow dial up type speeds in pages both loading and opening through those other browsers, and I am now feeling very frustrated in going onto the net at all presently, and I've just upgraded my data usage through my provider www.slingshot.co.nz from 40 to 80 gigs per month, but this is now also feeling like a lost cause as well. I am hoping someone at firefox may be able to help resolve this very troublesome issue, although I have also read some other stories contributed on this same matter, but I do not know if they were ever resolved either. Please help because I am now at my wits end upon it and have nothing else able to do, including what to do with the trouble shooter I downloaded at your suggestion from firefox - Thankyou.

Answer 1

Meanwhile, assuming the worst (malware), here are some suggestions for clean up.
Open the Windows '''Control Panel''', Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. Take out as much trash as possible here.
In particular, be on the lookout for Browser Safeguard (or similar name) or Sendori.
Then, in Firefox, open the '''Add-ons page''' using either:
* Ctrl+Shift+a
* "3-bar" menu button (or Tools menu) > Add-ons
In the left column, click Extensions. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions.
Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.
Finally, you can "mop up" remaining issues with the scanning/cleaning tools suggested in this support article: [[Troubleshoot Firefox issues caused by malware]].
Any change?