Firefox is excruciatingly slow to load web pages. The OS is Windows 10 Home 64-bit. 12.0 Gb RAM. The antivirus program is Defender. The Firewall is Windows. No other antivirus programs or firewalls. Refreshing does no good. Removing Add Ons makes no difference. Plug Ins are set to "Ask to Activate" except for Adobe Shockwave Flash, Primetime Content Decryption Module, OpenH264 Video Content which are always active. Firefox is much slower than Microsoft Edge. This was not a problem with Microsoft Vista Home Premium (but with a different computer). Incidentally, Thunderbird is also slow to download and send messages.