Windows 7 Locking Up With Firefox 91.0.1

My wife's laptop with Win7 keeps locking up when she is on the internet.
The only way to get off the internet is to shut down the computer with the power button.
Once it locks up the cursor keeps rotating as if it is trying to do something, but it does nothing until the power is shut off.
I have noticed that when MalwareBytes Premium 4.4.4 is running this problem occurs.
My question is this, is MalwareBytes causing the problem or is it something that FireFox has done to cause the problem?
I am at a loss on this problem and it has been going on now for about 30 days.
She is getting mad at me and that could be bad.
Any suggestions would be helpful and appreciated.

 

Try starting Firefox with add-ons disabled, also called Troubleshoot Mode

 

Thanks for the fast reply and I will check it out in the afternoon when I get back home.
Something else has also started today I am told and that is when she tried to open her photo folder she had a window explorer problem. She had to turn off the laptop to be able to close anything.
Like I said I will be checking things out as soon as I get back home. Work to much on the road now and getting tired of it.
Once again thanks for the information.

 

I will check that out once I get back home as I am out of town right now on business.
Thanks for the fast reply.

 

I am sorry for not able to post what I have checked out so far, but I just got back into town from business.

I tried a different browser on my wife's laptop and it still did the same thing. The browser is Brave.
I also disabled all the addons on FireFox 91.0.1 and tried it before installing Brave and having her try that one.
Malwarebytes was also disabled when trying to find the problem also.

Since doing the above things the laptop locked up 4 times and had to use the power button to turn it off for a restart of the unit.
If there is any other ideas as to what has been causing the problem I will check it out again.

Thank you

 

It may be nothing to do with Firefox, just that Firefox may be open most of the time so it just looks like a FF problem when it happens. Not a lot to go on but dust accumulations can cause such problems through overheating, and even blocking the air vents underneath with your clothing can too. Try blowing it through with a can of compressed air and do ensure it can't be her clothing causing it.