Why did my Dell computer using Firefox suddenly stop Speed Dial VFD stop it from working. have an older HP, works fine on it

Hello

Can you describe your problem?

got a message saying page is slowing the computer down. Do I want to wait or stop it I say stop it get does this two or three times and then the speed dial program is no longer working. When I choose to say wait the computer has completely Frozen up and at least once I had to restart it. Seems to be inside of Firefox but not chrome

Please tell me your version of Firefox.

whatever is latest.  It is constantly says updating. But will look next time have computers on