You may do better using Firefox Release (fx21), or Beta (fx22) *Firefox Nightly (fx25) is intended for developers and testing. *Why are you using Nightly ? *Note the 32bit beta willrunperfectly wellona64bitWindows computer. I use 32 bit Firefox versions in Windows on a 64 bit machine. Regardiing it looking like water I wonder if this is an issue with blurry fonts due to the Hi Dpi changes *[[Webpages are large and blurry after updating Firefox - how to fix]] Not sure I understand the explanation of the problem with tabs. Is it not loading ? if so see *[[Websites show a spinning wheel and never finish loading]] *[[Firefox can't load websites but other browsers can]] I presume Internet Explorer (IE) works ok.