Having problems with 52.8 ESR

I've had frequent freezing and Captcha errors from CL website on my old FF38 and had to update to 52.8 ESR (old machine winXP, SP2). For a few weeks Captcha worked - probably because I allowed cookies and got rid of NoScript. Placing CL and other sites in allowed Exceptions never worked. All cookies had to be allowed and kept till they expire. Now, even with everything allowed, including googleanalytics.com that I imagine must be allowed for Captcha to work, it still gives me errors on CL website. Last time - and now - I posted on this website I had to do Captcha a dozen times before it worked. CL forum did not help. Even bigger problem is that frequent freezing that's happening only in FF, When it freezes, task manager is not opening, double ended arrow in task bar does not allow for anything to be closed. when I manage to switch to TB window the part behind FF remains blank and I have no choice but press the power to shut down the laptop even though it does respond with the light on caps. I know it's an old laptop, but none of it is happening with other browsers and I would like to keep FF. Please help, thank you