lap top appears to be working normally then egg timer appears. When I go to move page down/up, white screen appears and page is frozen.
Only movement is to close down page. When I click x then box with two options appears. 1. Firefox is not responding
2. Do you want system to close itself (something like that)
Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).
If it does work in Safe-mode then disable all extensions and then try to find which is causing it by enabling one at a time until the problem reappears.