Solved! This link is hijacking browser

[Jack907]

Popup ....Important Firefox update available
Click install to continue ...

Can't escape it or close . Shutting down and rebooting Firefox is still hijacked

<<Suspicious link removed by moderator>>

 

[rgd1101]

can't see the image.

what happened after you click install?

 

[COLGeek]

Firefox typically does not present such pop-ups. You should scan your system for malware/viruses immediately.