Just got a blockage message and a number to call to address the possible issue while using Firefox

Hello Russell,
We are sorry to know that you are unable to use Mozilla Firefox and get stuck at a message to call. It seems that the Mozilla home page is hacked using the adware. Please do not call or respond to the message you receive in the Mozilla homepage. To fix this issue, we suggest you to reset the Mozilla firefox.

Have my Firefox Search engine blocked with message to call a number and to not shut off my computer…cannot close "warning" and requesting my user name and password…don't have a clue???
"A username and password are being requested byhttp://xxx.mysafesite.info.  The site  says "0x80070424 Microsoft Defender Alert: Hard Drive Failure!!!    Call Microsoft Helper Desk: +1-888-900-7553 (Toll Free)"

I have spoken with party at 800-239-5736  claiming to be a MS representative (MS444786)???

I have no idea whats going on…person I spoke with has very broken english.

No problems using Explore , Yahoo , Bling…seems to be restricted to Mozilla Fire Fox???

Hello Russell,
We are sorry to know that you are unable to use Mozilla Firefox and get stuck at a message to call. It seems that the Mozilla home page is hacked using the adware. Please do not call or respond to the message you receive in the Mozilla homepage. To fix this issue, we suggest you to reset the Mozilla firefox.

Please follow this steps to reset firefox
* In the upper-right corner of the Firefox window, click the Firefox menu button, then click on the “Help” button.
* From the Help menu, choose Troubleshooting Information.
If you’re unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting information page.
* Click the “Refresh Firefox” button in the upper-right corner of the “Troubleshooting Information” page.
* To continue, click on the “Refresh Firefox” button in the new confirmation window that opens.
* Firefox will close itself and will revert to its default settings. When it’s done, a window will list the information that was imported. Click on the “Finish“.
Thank you